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NCI Dictionary of Cancer Terms


310 results found for:       R



R-CHOP    listen  
An abbreviation for a chemotherapy combination that is used to treat non-Hodgkin lymphoma and mantle cell lymphoma and is being studied in the treatment of other types of cancer. It includes the drugs rituximab, cyclophosphamide, doxorubicin hydrochloride (hydroxydaunorubicin), vincristine sulfate (Oncovin), and prednisone. Also called R-CHOP regimen.

R-CHOP regimen    listen   (… REH-jih-men)
An abbreviation for a chemotherapy combination that is used to treat non-Hodgkin lymphoma and mantle cell lymphoma and is being studied in the treatment of other types of cancer. It includes the drugs rituximab, cyclophosphamide, doxorubicin hydrochloride (hydroxydaunorubicin), vincristine sulfate (Oncovin), and prednisone. Also called R-CHOP.

R-CVP      
An abbreviation for a chemotherapy combination used to treat indolent (slow-growing) non-Hodgkin lymphoma. It includes the drugs rituximab, cyclophosphamide, vincristine sulfate, and prednisone. Also called R-CVP regimen.

R-CVP regimen    listen   (… REH-jih-men)
An abbreviation for a chemotherapy combination used to treat indolent (slow-growing) non-Hodgkin lymphoma. It includes the drugs rituximab, cyclophosphamide, vincristine sulfate, and prednisone. Also called R-CVP.

R-flurbiprofen    listen   (… FLOOR-bih-PROH-fen)
A substance that is being studied as a treatment for cancer. It belongs to the family of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs).

r-metHuSCF      
A substance that causes blood stem cells (cells from which other types of cells develop) to change into different types of blood cells and increases the number and actions of these cells in the blood. It is being studied in the treatment of myelodysplasia. r-metHuSCF is a type of recombinant stem cell growth factor. Also called ancestim, recombinant human methionyl stem cell factor, and Stemgen.

r-tPA      
A form of tissue plasminogen activator that is made in the laboratory. It helps dissolve blood clots and is used to treat heart attacks, strokes, and clots in the lungs. It is also being studied in the treatment of cancer. It is a type of systemic thrombolytic agent. Also called Activase, Alteplase, and recombinant tissue plasminogen activator.

R101933      
A substance that is being studied for its ability to make cancer cells respond to drugs to which they have become resistant. It belongs to the family of drugs called multidrug resistance inhibitors.

R115777      
A substance that is being studied in the treatment of acute myeloid leukemia (AML) and other types of cancer. It belongs to the family of drugs called farnesyltransferase inhibitors. Also called tipifarnib and Zarnestra.

R1507      
A human monoclonal antibody being studied in the treatment of several types of cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. R1507 blocks the action of a protein needed for cell growth and may kill cancer cells. It is a type of insulin-like growth factor-1 receptor (IGF-1R) inhibitor.

R788 sodium    listen   (… SOH-dee-um)
A substance being studied in the treatment of cancer and certain other diseases, such as rheumatoid arthritis. It may block tumor cell signaling and growth. It is a type of tyrosine kinase inhibitor. Also called fostamatinib disodium and Syk kinase inhibitor R-935788.

rabies    listen   (RAY-beez)
A disease of the nervous system caused by the rabies virus. Rabies is marked by an increase in saliva production, abnormal behavior, and eventual paralysis and death.

rachitis    listen   (ray-KY-tis)
A condition in children in which bones become soft and deformed because they don’t have enough calcium and phosphorus. It is caused by not having enough vitamin D in the diet or by not getting enough sunlight. In adults, this condition is called osteomalacia. Also called infantile rickets, juvenile rickets, and rickets.

rAd/p53      
A substance that has been studied in the treatment of some types of cancer. rAd/p53 is a weakened adenovirus that carries the p53 gene into tumor cells, causing them to die. It is a type of gene therapy. Also called ACN53, recombinant adenovirus-p53, and SCH-58500.

RAD001      
A drug used with another drug to treat some postmenopausal women with advanced breast cancer that is hormone-receptor positive and HER2 negative. It is also used to treat certain types of pancreatic cancer, a type of advanced kidney cancer, and subependymal giant cell astrocytoma in some patients, including children. RAD001 is being studied in the treatment of other types of cancer. It stops cancer cells from dividing and may prevent the growth of new blood vessels that tumors need to grow. It also lowers the body’s immune response. It is a type of kinase inhibitor, a type of angiogenesis inhibitor, and a type of immunosuppressant. Also called Afinitor, Afinitor Disperz, and everolimus.

radiation    listen   (RAY-dee-AY-shun)
Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable).

radiation brachytherapy    listen   (RAY-dee-AY-shun BRAY-kee-THAYR-uh-pee)
A type of radiation therapy in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called brachytherapy, implant radiation therapy, and internal radiation therapy.

radiation dermatitis    listen   (RAY-dee-AY-shun DER-muh-TY-tis)
A skin condition that is a common side effect of radiation therapy. The affected skin becomes painful, red, itchy, and blistered.

radiation enteritis    listen   (RAY-dee-AY-shun EN-teh-RY-tis)
Inflammation of the small intestine caused by radiation therapy to the abdomen, pelvis, or rectum. Symptoms include nausea, vomiting, abdominal pain and cramping, frequent bowel movements, watery or bloody diarrhea, fatty stools, and weight loss. Some of these symptoms may continue for a long time.

radiation fibrosis    listen   (RAY-dee-AY-shun fy-BROH-sis)
The formation of scar tissue as a result of radiation therapy.

radiation necrosis    listen   (RAY-dee-AY-shun neh-KROH-sis)
The death of healthy tissue caused by radiation therapy. Radiation necrosis is a side effect of radiation therapy given to kill cancer cells, and can occur after cancer treatment has ended.

radiation nurse    listen   (RAY-dee-AY-shun nurs)
A health professional who specializes in caring for people who are receiving radiation therapy.

radiation oncologist    listen   (RAY-dee-AY-shun on-KAH-loh-jist)
A doctor who specializes in using radiation to treat cancer.

radiation physicist    listen   (RAY-dee-AY-shun FIH-zih-sist)
A person who makes sure that the radiation machine delivers the right amount of radiation to the correct site in the body. The physicist works with the radiation oncologist to choose the treatment schedule and dose that has the best chance of killing the most cancer cells.

radiation poisoning    listen   (RAY-dee-AY-shun POY-zuh-ning)
Serious illness caused by being exposed to high doses of certain types of radiation, usually over a short period of time. Symptoms of radiation poisoning usually occur right after exposure but they may happen over time, and they may come and go. Symptoms include nausea and vomiting, diarrhea, headache, dizziness, weakness, fatigue, bleeding, hair loss, swelling, itching, and redness of the skin, and other skin problems. Very large doses of radiation may cause death. Also called acute radiation sickness, acute radiation syndrome, radiation sickness, and radiation sickness syndrome.

radiation sickness    listen   (RAY-dee-AY-shun SIK-nes)
Serious illness caused by being exposed to high doses of certain types of radiation, usually over a short period of time. Symptoms of radiation sickness usually occur right after exposure but they may happen over time, and they may come and go. Symptoms include nausea and vomiting, diarrhea, headache, dizziness, weakness, fatigue, bleeding, hair loss, swelling, itching, and redness of the skin, and other skin problems. Very large doses of radiation may cause death. Also called acute radiation sickness, acute radiation syndrome, radiation poisoning, and radiation sickness syndrome.

radiation sickness syndrome    listen   (RAY-dee-AY-shun SIK-nes SIN-drome)
Serious illness caused by being exposed to high doses of certain types of radiation, usually over a short period of time. Symptoms of radiation sickness syndrome usually occur right after exposure but they may happen over time, and they may come and go. Symptoms include nausea and vomiting, diarrhea, headache, dizziness, weakness, fatigue, bleeding, hair loss, swelling, itching, and redness of the skin, and other skin problems. Very large doses of radiation may cause death. Also called acute radiation sickness, acute radiation syndrome, radiation poisoning, and radiation sickness.

radiation surgery    listen   (RAY-dee-AY-shun SER-juh-ree)
A type of external radiation therapy that uses special equipment to position the patient and precisely give a single large dose of radiation to a tumor. It is used to treat brain tumors and other brain disorders that cannot be treated by regular surgery. It is also being studied in the treatment of other types of cancer. Also called radiosurgery, stereotactic radiosurgery, and stereotaxic radiosurgery.

radiation therapist    listen   (RAY-dee-AY-shun THAYR-uh-pist)
A health professional who gives radiation treatment.

radiation therapy    listen   (RAY-dee-AY-shun THAYR-uh-pee)
The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

radical cervicectomy    listen   (RA-dih-kul SER-vih-SEK-toh-mee)
Surgery to remove the cervix, nearby tissue and lymph nodes, and the upper part of the vagina. It may be used to treat women with early-stage cervical cancer who want to have children. After the cervix is removed, the uterus is attached to the remaining part of the vagina. A special stitch or band is used to act as the cervix and create an opening to the uterus. The stitch or band may be opened or closed as needed. Also called radical trachelectomy.

radical cystectomy    listen   (RA-dih-kul sis-TEK-toh-mee)
Surgery to remove all of the bladder (the organ that holds urine) as well as nearby tissues and organs.

radical hysterectomy    listen   (RA-dih-kul HIS-teh-REK-toh-mee)
Surgery to remove the uterus, cervix, and part of the vagina. The ovaries, fallopian tubes, and nearby lymph nodes may also be removed.

radical local excision    listen   (RA-dih-kul LOH-kul ek-SIH-zhun)
Surgery to remove a tumor and a large amount of normal tissue surrounding it. Nearby lymph nodes may also be removed.

radical lymph node dissection    listen   (RA-dih-kul limf node dy-SEK-shun)
A surgical procedure to remove most or all of the lymph nodes that drain lymph from the area around a tumor. The lymph nodes are then examined under a microscope to see if cancer cells have spread to them.

radical mastectomy    listen   (RA-dih-kul ma-STEK-toh-mee)
Surgery for breast cancer in which the breast, chest muscles, and all of the lymph nodes under the arm are removed. For many years, this was the breast cancer operation used most often, but it is used rarely now. Doctors consider radical mastectomy only when the tumor has spread to the chest muscles. Also called Halsted radical mastectomy.

radical nephrectomy    listen   (RA-dih-kul neh-FREK-toh-mee)
Surgery to remove an entire kidney, nearby adrenal gland and lymph nodes, and other surrounding tissue.

radical perineal prostatectomy    listen   (RA-dih-kul PAYR-ih-NEE-ul PROS-tuh-TEK-toh-mee)
Surgery to remove all of the prostate through an incision between the scrotum and the anus. Nearby lymph nodes are sometimes removed through a separate incision in the wall of the abdomen.

radical prostatectomy    listen   (RA-dih-kul PROS-tuh-TEK-toh-mee)
Surgery to remove the entire prostate and some of the tissue around it. Nearby lymph nodes may also be removed. In a radical retropubic prostatectomy, an incision (cut) is made in the wall of the lower abdomen. In a radical perineal prostatectomy, an incision (cut) is made in the perineum (the area between the anus and scrotum). In a laparoscopic radical prostatectomy, several small incisions (cuts) are made in the wall of the abdomen. A laparoscope (a thin, tube-like instrument with a light and lens for viewing) is inserted through one opening to guide the surgery. Surgical instruments are inserted through the other openings to do the surgery.

radical retropubic prostatectomy    listen   (RA-dih-kul reh-troh-PYOO-bik PROS-tuh-TEK-toh-mee)
Surgery to remove all of the prostate and nearby lymph nodes through an incision in the wall of the abdomen.

radical trachelectomy    listen   (RA-dih-kul TRAY-kee-LEK-toh-mee)
Surgery to remove the cervix, nearby tissue and lymph nodes, and the upper part of the vagina. It may be used to treat women with early-stage cervical cancer who want to have children. After the cervix is removed, the uterus is attached to the remaining part of the vagina. A special stitch or band is used to act as the cervix and create an opening to the uterus. The stitch or band may be opened or closed as needed. Also called radical cervicectomy.

radical vulvectomy    listen   (RA-dih-kul vul-VEK-toh-mee)
Surgery to remove the entire vulva (the external female genital organs, including the clitoris, vaginal lips, and the opening to the vagina) and nearby lymph nodes.

radio wave    listen   (RAY-dee-oh…)
A type of wave made when an electric field and a magnetic field are combined. Radio waves are being studied in the treatment of several types of cancer and other conditions. The radio waves are sent through needles inserted into tumor tissue and may kill cancer cells. Radio waves are also used in MRI to create detailed images of areas inside the body.

radioactive    listen   (RAY-dee-oh-AK-tiv)
Giving off radiation.

radioactive drug    listen   (RAY-dee-oh-AK-tiv...)
A drug that contains a radioactive substance and is used to diagnose or treat disease, including cancer. Also called radiopharmaceutical.

radioactive fallout    listen   (RAY-dee-oh-AK-tiv...)
Airborne radioactive particles that fall to the ground during and after an atomic bombing, nuclear weapons test, or nuclear plant accident.

radioactive iodine    listen   (RAY-dee-oh-AK-tiv I-oh-dine)
A radioactive form of iodine, often used for imaging tests or to treat an overactive thyroid, thyroid cancer, and certain other cancers. For imaging tests, the patient takes a small dose of radioactive iodine that collects in thyroid cells and certain kinds of tumors and can be detected by a scanner. To treat thyroid cancer, the patient takes a large dose of radioactive iodine, which kills thyroid cells. Radioactive iodine is also used in internal radiation therapy for prostate cancer, intraocular (eye) melanoma, and carcinoid tumors. Radioactive iodine is given by mouth as a liquid or in capsules, by infusion, or sealed in seeds, which are placed in or near the tumor to kill cancer cells.

radioactive palladium    listen   (RAY-dee-oh-AK-tiv puh-LAY-dee-um)
A radioactive form of palladium (a metallic element that resembles platinum). When used to treat prostate cancer, radioactive seeds (small pellets that contain radioactive palladium) are placed in the prostate. Cancer cells are killed by the energy given off as the radioactive material breaks down and becomes more stable.

radioactive seed    listen   (RAY-dee-oh-AK-tiv...)
A small, radioactive pellet that is placed in or near a tumor. Cancer cells are killed by the energy given off as the radioactive material breaks down and becomes more stable.

radioembolization    listen   (RAY-dee-oh-EM-boh-lih-ZAY-shun)
A type of radiation therapy used to treat liver cancer that is advanced or has come back. Tiny beads that hold the radioisotope yttrium Y 90 are injected into the hepatic artery (the main blood vessel that carries blood to the liver). The beads collect in the tumor and the yttrium Y 90 gives off radiation. This destroys the blood vessels that the tumor needs to grow and kills the cancer cells. Radioembolization is a type of selective internal radiation therapy (SIRT). Also called intra-arterial brachytherapy.

radiofrequency ablation    listen   (RAY-dee-oh-FREE-kwen-see a-BLAY-shun)
A procedure that uses radio waves to heat and destroy abnormal cells. The radio waves travel through electrodes (small devices that carry electricity). Radiofrequency ablation may be used to treat cancer and other conditions.

radioimaging    listen   (RAY-dee-oh-IH-muh-jing)
A method that uses radioactive substances to make pictures of areas inside the body. The radioactive substance is injected into the body, and locates and binds to specific cells or tissues, including cancer cells. Images are made using a special machine that detects the radioactive substance. Also called nuclear medicine scan.

radioimmunoconjugate    listen   (RAY-dee-oh-IH-myoo-noh-KON-jih-gut)
A radioactive substance that carries radiation directly to cancer cells. A radioimmunoconjugate is made by attaching a radioactive molecule to an immune substance, such as a monoclonal antibody, that can bind to cancer cells. This may help kill cancer cells without harming normal cells. Radioimmunoconjugates may also be used with imaging to help find cancer cells in the body.

radioimmunodiagnostics    listen   (RAY-dee-oh-IH-myoo-noh-DY-ug-NOS-tix)
The use of radiolabeled monoclonal antibodies to help diagnose diseases, including cancer. The radiolabeled monoclonal antibody locates and binds to substances in the body, including cancer cells. Images are made using a special machine that detects the radioactive monoclonal antibody.

radioimmunoguided surgery    listen   (RAY-dee-oh-IH-myoo-noh-GY-ded SER-juh-ree)
A procedure that uses radioactive substances to locate tumors so that they can be removed by surgery.

radioimmunotherapeutics    listen   (RAY-dee-oh-IH-myoo-noh-THAYR-uh-PYOO-tix)
The use of radiolabeled monoclonal antibodies to treat diseases, including cancer. The radiolabeled monoclonal antibody locates and binds to substances in the body, including cancer cells. Radiation given off by the radioisotope may help kill the cancer cells.

radioimmunotherapy    listen   (RAY-dee-oh-IH-myoo-noh-THAYR-uh-pee)
A type of radiation therapy in which a radioactive substance is linked to a monoclonal antibody and injected into the body. The monoclonal antibody can bind to substances in the body, including cancer cells. The radioactive substance gives off radiation, which may help kill cancer cells. Radioimmunotherapy is being used to treat some types of cancer, such as lymphoma.

radioisotope    listen   (RAY-dee-oh-I-suh-tope)
An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable. Radioisotopes may occur in nature or be made in a laboratory. In medicine, they are used in imaging tests and in treatment. Also called radionuclide.

radiolabeled    listen   (RAY-dee-oh-LAY-buld)
Any compound that has been joined with a radioactive substance.

radiologic exam    listen   (RAY-dee-oh-LAH-jik eg-ZAM)
A test that uses radiation or other imaging procedures to find signs of cancer or other abnormalities.

radiologist    listen   (RAY-dee-AH-loh-jist)
A doctor who specializes in creating and interpreting pictures of areas inside the body. The pictures are produced with x-rays, sound waves, or other types of energy.

radiology    listen   (RAY-dee-AH-loh-jee)
The use of radiation (such as x-rays) or other imaging technologies (such as ultrasound and magnetic resonance imaging) to diagnose or treat disease.

radionuclide    listen   (RAY-dee-oh-NOO-klide)
An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable. Radionuclides may occur in nature or be made in a laboratory. In medicine, they are used in imaging tests and in treatment. Also called radioisotope.

radionuclide scanning       (RAY-dee-oh-NOO-klide SKAN-ing)
A procedure that produces pictures (scans) of structures inside the body, including areas where there are cancer cells. Radionuclide scanning is used to diagnose, stage, and monitor disease. A small amount of a radioactive chemical (radionuclide) is injected into a vein or swallowed. Different radionuclides travel through the blood to different organs. A machine with a special camera moves over the person lying on a table and detects the type of radiation given off by the radionuclides. A computer forms an image of the areas where the radionuclide builds up. These areas may contain cancer cells. Also called scintigraphy.

radiopharmaceutical    listen   (RAY-dee-oh-FAR-muh-SOO-tih-kul)
A drug that contains a radioactive substance and is used to diagnose or treat disease, including cancer. Also called radioactive drug.

radiosensitization    listen   (RAY-dee-oh-SEN-sih-tih-ZAY-shun)
The use of a drug that makes tumor cells more sensitive to radiation therapy.

radiosensitizer    listen   (RAY-dee-oh-SEN-sih-TY-zer)
Any substance that makes tumor cells easier to kill with radiation therapy. Some radiosensitizers are being studied in the treatment of cancer. Also called radiosensitizing agent.

radiosensitizing agent    listen   (RAY-dee-oh-SEN-sih-TY-zing AY-jent)
Any substance that makes tumor cells easier to kill with radiation therapy. Some radiosensitizing agents are being studied in the treatment of cancer. Also called radiosensitizer.

radiosurgery    listen   (RAY-dee-oh-SER-juh-ree)
A type of external radiation therapy that uses special equipment to position the patient and precisely give a single large dose of radiation to a tumor. It is used to treat brain tumors and other brain disorders that cannot be treated by regular surgery. It is also being studied in the treatment of other types of cancer. Also called radiation surgery, stereotactic radiosurgery, and stereotaxic radiosurgery.

radiotherapy    listen   (RAY-dee-oh-THAYR-uh-pee)
The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiotherapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiation therapy.

radium 223 dichloride    listen   (RAY-dee-um … dy-KLOR-ide)
A drug used to treat prostate cancer that has spread to the bone and has not gotten better with other treatment. It is also being studied in the treatment of other types of cancer. Radium 223 dichloride contains a radioactive substance called radium 223. Radium 223 collects in bone and gives off radiation that may kill cancer cells. Radium 223 dichloride is a type of radiopharmaceutical. Also called Xofigo.

radon    listen   (RAY-don)
A radioactive gas that is released by uranium, a substance found in soil and rock. Breathing in too much radon can damage lung cells and may lead to lung cancer.

Raftilose Synergy 1    listen   (RAF-tih-lose SIH-ner-jee ...)
A substance that is used to improve the health of the digestive system and bones and is being studied in the prevention of colon cancer. Raftilose Synergy 1 is made by combining two substances that occur naturally in many plants, including chicory root, wheat, bananas, onion, and garlic. Raftilose Synergy 1 helps healthy bacteria grow in the intestines and helps the body absorb calcium and magnesium. Also called oligofructose-enriched inulin.

raloxifene    listen   (ra-LOK-sih-feen)
The active ingredient in a drug used to reduce the risk of invasive breast cancer in postmenopausal women who are at high risk of the disease or who have osteoporosis. It is also used to prevent and treat osteoporosis in postmenopausal women. It is also being studied in the prevention of breast cancer in certain premenopausal women and in the prevention and treatment of other conditions. Raloxifene blocks the effects of the hormone estrogen in the breast and increases the amount of calcium in bone. It is a type of selective estrogen receptor modulator (SERM).

raloxifene hydrochloride    listen   (ra-LOK-sih-feen HY-droh-KLOR-ide)
A drug used to reduce the risk of invasive breast cancer in postmenopausal women who are at high risk of the disease or who have osteoporosis. It is also used to prevent and treat osteoporosis in postmenopausal women. It is also being studied in the prevention of breast cancer in certain premenopausal women and in the prevention and treatment of other conditions. Raloxifene hydrochloride blocks the effects of the hormone estrogen in the breast and increases the amount of calcium in bone. It is a type of selective estrogen receptor modulator (SERM). Also called Evista.

raltitrexed    listen   (RAL-tih-TREK-sed)
An anticancer drug that stops tumor cells from growing by blocking the ability of cells to make DNA. It belongs to the family of drugs called thymidylate synthase inhibitors. Also called ICI D1694.

ramucirumab    listen   (RA-myoo-SIR-yoo-mab)
A drug used with docetaxel to treat non-small cell lung cancer (NSCLC) that has spread to other parts of the body. It is also used alone or with paclitaxel to treat cancer of the stomach or gastroesophageal junction (area where the esophagus connects to the stomach) that is advanced or has spread to other parts of the body. Ramucirumab is used in patients whose cancer has gotten worse after treatment with other anticancer drugs. It is also being studied in the treatment of other types of cancer. Ramucirumab binds to receptors for a protein called vascular endothelial growth factor (VEGF), which may be found on some types of cancer cells. This may prevent the growth of new blood vessels that tumors need to grow. Ramucirumab is a type of antiangiogenesis agent and a type of monoclonal antibody. Also called anti-VEGFR-2 fully human monoclonal antibody IMC-1121B, Cyramza, and IMC-1121B.

randomization    listen   (RAN-duh-mih-ZAY-shun)
When referring to an experiment or clinical trial, the process by which animal or human subjects are assigned by chance to separate groups that compare different treatments or other interventions. Randomization gives each participant an equal chance of being assigned to any of the groups.

randomized clinical trial    listen   (RAN-duh-mized KLIH-nih-kul TRY-ul)
A study in which the participants are assigned by chance to separate groups that compare different treatments; neither the researchers nor the participants can choose which group. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively. At the time of the trial, it is not known which treatment is best. It is the patient's choice to be in a randomized trial.

ranpirnase    listen   (RAN-per-nays)
A substance being studied in the treatment of cancer. It is a type of ribonuclease enzyme. Also called Onconase.

Rapamune    listen   (RA-puh-MYOON)
A drug used to keep the body from rejecting organ and bone marrow transplants. Rapamune blocks certain white blood cells that can reject foreign tissues and organs. It also blocks a protein that is involved in cell division. It is a type of antibiotic, a type of immunosuppressant, and a type of serine/threonine kinase inhibitor. Rapamune was previously called rapamycin. Also called sirolimus.

rapamycin    listen   (RA-puh-MY-sin)
A drug used to keep the body from rejecting organ and bone marrow transplants. Rapamycin blocks certain white blood cells that can reject foreign tissues and organs. It also blocks a protein that is involved in cell division. It is a type of antibiotic, a type of immunosuppressant, and a type of serine/threonine kinase inhibitor. Rapamycin is now called sirolimus.

rapid eye movement sleep    listen   (RA-pid I MOOV-ment sleep)
One of the five stages of sleep. During rapid eye movement sleep, the eyes move rapidly while closed and dreams occur. Rapid eye movement sleep is the lightest stage of sleep, during which a person may wake easily. During several hours of normal sleep, a person will go through several sleep cycles that include rapid eye movement sleep and the 4 stages of non-rapid eye movement (light to deep sleep). Also called REM sleep.

rapid hormone cycling    listen   (RA-pid HOR-mone SY-kuh-ling)
A procedure in which drugs that block the production of male hormones are alternated with male hormones and/or drugs that promote the production of male hormones. This procedure is being studied in the treatment of prostate cancer.

rapid-onset opioid    listen   (… OH-pee-OYD)
A substance that acts quickly to treat moderate to severe pain. Opioids are like opiates, such as morphine and codeine, but are not made from opium. Opioids bind to opioid receptors in the central nervous system. A rapid-onset opioid is a type of alkaloid.

ras gene family    listen   (... jeen FA-mih-lee)
A family of genes that may cause cancer when they are mutated (changed). They make proteins that are involved in cell signaling pathways, cell growth, and apoptosis (cell death). Agents that block the actions of a mutated ras gene or its protein may stop the growth of cancer. Members of the ras gene family include Kras, Hras, and Nras.

ras peptide    listen   (ras PEP-tide)
A short piece of the ras protein, which is made by the ras gene. The ras gene has been found to cause cancer when it is mutated (changed).

rasburicase    listen   (ras-BUR-ih-kays)
A drug used to treat high blood levels of uric acid in patients with leukemia, lymphoma, and other types of cancer who are receiving certain types of cancer treatment. It is also being studied in the treatment of other medical conditions. Rasburicase is a type of recombinant enzyme and a type of urate-lowering drug. Also called Elitek and recombinant urate oxidase.

rattlesnake root    listen   (RA-til-SNAYK root)
An eastern North American perennial herb. A substance obtained from the root of the plant has been used in some cultures to treat a number of medical problems. It is being studied in the treatment of hot flashes and other symptoms of menopause. The scientific name is Cimicifuga racemosa. Also called black cohosh, black snakeroot, bugbane, and bugwort.

rauschpfeffer    listen   (ROWSH-feh-fer)
An herb native to islands in the South Pacific. Substances taken from the root have been used in some cultures to relieve stress, anxiety, tension, sleeplessness, and problems of menopause. Rauschpfeffer may increase the effect of alcohol and of certain drugs used to treat anxiety and depression. The U.S. Food and Drug Administration advises users that rauschpfeffer may cause severe liver damage. The scientific name is Piper methysticum. Also called intoxicating pepper, kava kava, tonga, and yangona.

RAV12      
A monoclonal antibody that is being studied in the treatment of some types of cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to cancer cells. It binds to a carbohydrate (sugar) molecule that is found on gastric, colon, pancreatic, prostate, ovarian, breast, and kidney cancer cells.

ravuconazole    listen   (RA-vuh-KAH-nuh-zole)
A substance that is being studied in the treatment of infections caused by fungi. It belongs to the family of drugs called antifungal agents.

RBC      
A type of blood cell that is made in the bone marrow and found in the blood. RBCs contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body. Checking the number of RBCs in the blood is usually part of a complete blood cell (CBC) test. It may be used to look for conditions such as anemia, dehydration, malnutrition, and leukemia. Also called erythrocyte and red blood cell.

reactivate    listen   (ree-AK-tih-VAYT)
To make active again or make something work again. In medicine, an infection or a disease is described as reactivated when it comes back after a period with no signs of disease.

reactive oxygen species    listen   (ree-AK-tive OK-sih-jen SPEE-sees)
A type of unstable molecule that contains oxygen and that easily reacts with other molecules in a cell. A build up of reactive oxygen species in cells may cause damage to DNA, RNA, and proteins, and may cause cell death. Reactive oxygen species are free radicals. Also called oxygen radical.

reagent    listen   (ree-AY-jent)
A substance used to carry out a laboratory test. Reagents may be used in a chemical reaction to detect, measure, or make other substances.

rebeccamycin    listen   (reh-BEH-kuh-MY-sin)
A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called antineoplastic antibiotics.

rebeccamycin analog    listen   (reh-BEH-kuh-MY-sin A-nuh-log)
A substance that is being studied in the treatment of cancer. It belongs to the families of drugs called antitumor antibiotics and topoisomerase inhibitors. Also called NSC 655649.

Recentin    listen   (reh-SEN-tin)
A substance being studied in the treatment of some types of cancer. Recentin may prevent the growth of new blood vessels that tumors need to grow and may kill cancer cells. It is a type of antiangiogenesis agent and a type of vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor. Also called AZD2171 and cediranib maleate.

receptor    listen   (reh-SEP-ter)
A molecule inside or on the surface of a cell that binds to a specific substance and causes a specific effect in the cell.

recipient    listen   (reh-SIH-pee-ent)
In medicine, a person who receives blood, cells, tissue, or an organ from another person, such as in a blood transfusion or an organ transplant.

RECIST    listen  
A standard way to measure how well a cancer patient responds to treatment. It is based on whether tumors shrink, stay the same, or get bigger. To use RECIST, there must be at least one tumor that can be measured on x-rays, CT scans, or MRI scans. The types of response a patient can have are a complete response (CR), a partial response (PR), progressive disease (PD), and stable disease (SD). Also called Response Evaluation Criteria In Solid Tumors.

recombinant    listen   (ree-KOM-bih-nunt)
In genetics, describes DNA, proteins, cells, or organisms that are made by combining genetic material from two different sources. Recombinant substances are made in the laboratory and are being studied in the treatment of cancer and for many other uses.

recombinant adenovirus-p53    listen   (ree-KOM-bih-nunt A-den-oh-VY-rus ...)
A substance that has been studied in the treatment of some types of cancer. Recombinant adenovirus-p53 is a weakened adenovirus that carries the p53 gene into tumor cells, causing them to die. It is a type of gene therapy. Also called ACN53, rAd/p53, and SCH-58500.

recombinant fowlpox-CEA-MUC-1-TRICOM vaccine    listen   (ree-KOM-bih-nunt … vak-SEEN)
A cancer vaccine made with a form of a chicken virus that does not cause disease in humans. It is being studied in the treatment of some types of cancer. The virus is changed in the laboratory to make human proteins that may help immune cells in the body kill tumor cells. Also called falimarev.

recombinant fowlpox-TRICOM vaccine    listen   (ree-KOM-bih-nunt … vak-SEEN)
A cancer vaccine made with a form of a chicken virus that does not cause disease in humans. It is being studied in the treatment of some types of cancer. The virus is changed in the laboratory to make human proteins that may help immune cells in the body kill tumor cells. Also called rF-TRICOM.

recombinant human interleukin-2    listen   (ree-KOM-bih-nunt HYOO-mun in-ter-LOO-kin...)
A drug used to treat some types of cancer. It is a form of interleukin-2, a cytokine made by leukocytes (white blood cells), that is made in the laboratory. Recombinant human interleukin-2 increases the activity and growth of white blood cells called T lymphocytes and B lymphocytes. It is a type of biological response modifier. Also called aldesleukin and Proleukin.

recombinant human interleukin-11    listen   (ree-KOM-bih-nunt HYOO-mun in-ter-LOO-kin...)
A drug used to increase the number of blood cells, especially platelets, in some cancer patients receiving chemotherapy. Recombinant human interleukin-11 is a form of interleukin-11 (a cytokine normally made by support cells in the bone marrow) that is made in the laboratory. It is a type of biological response modifier. Also called Neumega, oprelvekin, and rhIL-11.

recombinant human methionyl stem cell factor    listen   (ree-KOM-bih-nunt HYOO-mun meh-THY-oh-nil stem sel FAK-ter)
A substance that causes blood stem cells (cells from which other types of cells develop) to change into different types of blood cells and increases the number and actions of these cells in the blood. It is being studied in the treatment of myelodysplasia. Recombinant human methionyl stem cell factor is a type of recombinant stem cell growth factor. Also called ancestim, r-metHuSCF, and Stemgen.

recombinant human papillomavirus bivalent vaccine    listen   (ree-KOM-bih-nunt HYOO-mun PA-pih-LOH-muh-VY-rus by-VAY-lent vak-SEEN)
A vaccine used to prevent cervical cancer caused by human papillomavirus (HPV) types 16 and 18. Recombinant human papillomavirus bivalent vaccine is approved for use in females aged 9 to 25 years. It is a type of bivalent vaccine (a vaccine that works against two different viruses or other microorganisms). Also called Cervarix.

recombinant human papillomavirus quadrivalent vaccine    listen   (ree-KOM-bih-nunt HYOO-mun PA-pih-LOH-muh-VY-rus KWAH-drih-VAY-lent vak-SEEN)
A vaccine used to prevent anal, cervical, vulvar, and vaginal cancer caused by human papillomavirus (HPV) types 16 and 18 and genital warts caused by HPV types 6 and 11. Recombinant human papillomavirus quadrivalent vaccine is approved for use in males and females aged 9 to 26 years. It is a type of quadrivalent vaccine (a vaccine that works against four different viruses or other microorganisms). Also called Gardasil.

recombinant interferon alfa-2b    listen   (ree-KOM-bih-nunt in-ter-FEER-on AL-fuh …)
A drug used to treat AIDS-related Kaposi sarcoma in certain patients, hairy cell leukemia, and melanoma that has been removed by surgery. It is also used with other anticancer drugs to treat a certain type of non-Hodgkin lymphoma. Recombinant interferon alfa-2b is also used to treat some infections caused by viruses, such as the hepatitis C virus. It is being studied in the treatment of other types of cancer and other conditions. Recombinant interferon alfa-2b is a form of interferon alfa (a substance normally made by cells in the immune system) and is made in the laboratory. It is a type of cytokine and a type of biological response modifier. Also called IFN alpha-2B, interferon alfa-2b, and Intron A.

recombinant tissue plasminogen activator    listen   (ree-KOM-bih-nunt TIH-shoo plaz-MIN-oh-jen AK-tih-vay-ter)
A form of tissue plasminogen activator that is made in the laboratory. It helps dissolve blood clots and is used to treat heart attacks, strokes, and clots in the lungs. It is also being studied in the treatment of cancer. It is a type of systemic thrombolytic agent. Also called Activase, Alteplase, and r-tPA.

recombinant urate oxidase    listen   (ree-KOM-bih-nunt YOOR-ayt OK-sih-days)
A drug used to treat high blood levels of uric acid in patients with leukemia, lymphoma, and other types of cancer who are receiving certain types of cancer treatment. It is also being studied in the treatment of other medical conditions. Recombinant urate oxidase is a type of recombinant enzyme and a type of urate-lowering drug. Also called Elitek and rasburicase.

recombinant vaccinia-CEA-MUC-1-TRICOM vaccine    listen   (ree-KOM-bih-nunt vak-SIH-nee-uh … vak-SEEN)
A cancer vaccine made with a form of vaccinia virus that does not cause disease in humans. It is being studied in the treatment of some types of cancer. The virus is changed in the laboratory to make human proteins, including the tumor markers called CEA and MUC-1, that may help immune cells in the body kill tumor cells. Also called inalimarev and PANVAC-V.

recombinant vaccinia-TRICOM vaccine    listen   (ree-KOM-bih-nunt vak-SIH-nee-uh … vak-SEEN)
A cancer vaccine made with a form of a vaccinia virus that does not cause disease in humans. It is being studied in the treatment of some types of cancer. The virus is changed in the laboratory to make human proteins that may help immune cells in the body kill tumor cells. Also called rV-TRICOM and vaccinia-TRICOM vaccine.

reconstructive surgeon    listen   (REE-kun-STRUK-tiv SER-jun)
A doctor who can surgically reshape or rebuild (reconstruct) a part of the body, such as a woman's breast after surgery for breast cancer.

reconstructive surgery    listen   (REE-kun-STRUK-tiv SER-juh-ree)
Surgery that is done to reshape or rebuild (reconstruct) a part of the body changed by previous surgery.

recover    listen   (ree-KUH-ver)
To become well and healthy again.

recreational therapy    listen   (REH-kree-AY-shuh-nul THAYR-uh-pee)
A type of therapy that uses activities to help meet the physical and emotional needs of patients with an illness or disability and help them develop skills for daily living. These activities include arts and crafts, music, spending time with animals, sports, and drama. Recreational therapy is being studied as a way to relieve distress in cancer patients who are being treated for pain.

rectal    listen   (REK-tul)
By or having to do with the rectum. The rectum is the last several inches of the large intestine closest to the anus.

rectal cancer    listen   (REK-tul KAN-ser)
Cancer that forms in the tissues of the rectum (the last several inches of the large intestine closest to the anus).

rectal reconstruction    listen   (REK-tul REE-kun-STRUK-shun)
Surgery to rebuild the rectum (the last several inches of the large intestine before the anus) using a section of the colon. This may be done when the rectum has been removed to treat cancer or other diseases.

rectitis    listen   (rek-TY-tis)
Inflammation of the mucous membrane that lines the rectum (the last several inches of the large intestine closest to the anus). Also called proctitis.

rectum    listen   (REK-tum)
The last several inches of the large intestine closest to the anus.

recur    listen   (ree-KER)
To come back or to return.

recurrence    listen   (ree-KER-ents)
Cancer that has recurred (come back), usually after a period of time during which the cancer could not be detected. The cancer may come back to the same place as the original (primary) tumor or to another place in the body. Also called recurrent cancer.

recurrent cancer    listen   (ree-KER-ent KAN-ser)
Cancer that has recurred (come back), usually after a period of time during which the cancer could not be detected. The cancer may come back to the same place as the original (primary) tumor or to another place in the body. Also called recurrence.

red blood cell    listen   (red blud sel)
A type of blood cell that is made in the bone marrow and found in the blood. Red blood cells contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body. Checking the number of red blood cells in the blood is usually part of a complete blood cell (CBC) test. It may be used to look for conditions such as anemia, dehydration, malnutrition, and leukemia. Also called erythrocyte and RBC.

red cedar    listen   (red SEE-der)
A type of evergreen tree with hard fragrant wood that is a member of the cypress family. The oil from the wood is used in soaps, shampoos, bath salts, perfumes, aromatherapy, and to keep insects away. The scientific name is Juniperus virginiana. Also called cedarwood and Eastern red cedar.

red clover    listen   (red KLOH-ver)
Trifolium pratense. A plant with flowers that has been used in some cultures to treat certain medical problems. It is being studied in the relief of menopausal symptoms and may have anticancer effects. Also called purple clover, Trifolium pratense, and wild clover.

red date    listen   (red dayt)
The fruit of the jujube plant. It has been used in some cultures to treat certain medical problems.

red elm    listen   (red elm)
The inner bark of this plant has been used in some cultures to treat certain medical problems. It may have antioxidant effects. Also called gray elm, Indian elm, slippery elm, sweet elm, Ulmus fulva, and Ulmus rubra.

reduction    listen   (ree-DUK-shun)
A chemical reaction that takes place when a substance comes into contact with hydrogen or another reducing substance.

Reed-Sternberg cell    listen   (reed-STERN-berg sel)
A type of cell that appears in people with Hodgkin disease. The number of these cells increases as the disease advances.

reference interval    listen   (REH-frents IN-ter-vul)
In medicine, a set of values that a doctor uses to interpret a patient’s test results. The reference interval for a given test is based on the results that are seen in 95% of the healthy population. Sometimes patients whose test results are outside of the reference interval may be healthy, and some patients whose test results are within the reference interval may have a health problem. The reference interval for a test may be different for different groups of people (for example, men and women). Also called normal range, reference range, and reference values.

reference range    listen   (REH-frents raynj)
In medicine, a set of values that a doctor uses to interpret a patient’s test results. The reference range for a given test is based on the results that are seen in 95% of the healthy population. Sometimes patients whose test results are outside of the reference range may be healthy, and some patients whose test results are within the reference range may have a health problem. The reference range for a test may be different for different groups of people (for example, men and women). Also called normal range, reference interval, and reference values.

reference values    listen   (REH-frents VAL-yooz)
In medicine, a set of values that a doctor uses to interpret a patient’s test results. The reference values for a given test are based on the results that are seen in 95% of the healthy population. Sometimes patients whose test results are outside of the reference values may be healthy, and some patients whose test results are within the reference values may have a health problem. The reference values for a test may be different for different groups of people (for example, men and women). Also called normal range, reference interval, and reference range.

referral    listen   (reh-FER-ul)
In medicine, the act of a doctor in which a patient is sent to another doctor for additional healthcare services.

reflexology    listen   (ree-flek-SAH-loh-jee)
A type of massage in which different amounts of pressure are applied to specific points on the feet or hands. These points are believed to match up with certain other parts of the body. Reflexology is claimed to cause relaxation and healing in those parts of the body, but this has not been proven.

reflux    listen   (REE-fluks)
The backward flow of liquid from the stomach into the esophagus.

refractory    listen   (reh-FRAK-tor-ee)
In medicine, describes a disease or condition that does not respond to treatment.

refractory cancer    listen   (reh-FRAK-tor-ee KAN-ser)
Cancer that does not respond to treatment. The cancer may be resistant at the beginning of treatment or it may become resistant during treatment. Also called resistant cancer.

Regenecare    listen   (reh-JEH-neh-KAYR)
A substance being studied in the treatment of certain types of skin rash and skin pain in cancer patients. The ingredients of Regenecare are collagen, aloe vera, vitamin E, and lidocaine. It may help stop bleeding, form new blood vessels, keep the skin moist, and relieve pain and itching. It is a type of topical anesthetic and a type of wound repair agent.

regeneration    listen   (ree-JEH-neh-RAY-shun)
In biology, regrowth of damaged or destroyed tissue or body part.

regimen    listen   (REH-jih-men)
A treatment plan that specifies the dosage, the schedule, and the duration of treatment.

regional    listen   (REE-juh-nul)
In oncology, describes the body area right around a tumor.

regional anesthesia    listen   (REE-juh-nul A-nes-THEE-zhuh)
A temporary loss of feeling or awareness in a part of the body, such as an arm or a leg, caused by special drugs or other substances called anesthetics. The patient stays awake but has no feeling in the part of the body treated with the anesthetic.

regional cancer    listen   (REE-juh-nul KAN-ser)
Refers to cancer that has grown beyond the original (primary) tumor to nearby lymph nodes or organs and tissues.

regional chemotherapy    listen   (REE-juh-nul KEE-moh-THAYR-uh-pee)
Treatment with anticancer drugs directed to a specific area of the body.

regional enteritis    listen   (REE-juh-nul EN-teh-RY-tis)
A condition in which the gastrointestinal tract is inflamed over a long period of time. Regional enteritis usually affects the small intestine and colon. Symptoms include fever, diarrhea, stomach cramps, vomiting, and weight loss. Regional enteritis increases the risk of colorectal cancer and small intestine cancer. It is a type of inflammatory bowel disease (IBD). Also called Crohn disease.

regional lymph node    listen   (REE-juh-nul limf node)
In oncology, a lymph node that drains lymph from the region around a tumor.

regional lymph node dissection    listen   (REE-juh-nul limf node dy-SEK-shun)
A surgical procedure to remove some of the lymph nodes that drain lymph from the area around a tumor. The lymph nodes are then examined under a microscope to see if cancer cells have spread to them.

registered dietitian    listen   (...dy-eh-TIH-shun)
A health professional with special training in the use of diet and nutrition to keep the body healthy. A registered dietitian may help the medical team improve the nutritional health of a patient.

Reglan    listen   (REG-lun)
A drug that increases the motility (movements and contractions) of the stomach and upper intestine. It is used to treat certain stomach problems and nausea and vomiting caused by chemotherapy. It is a type of antiemetic and a type of motility agent. Also called metoclopramide.

regorafenib    listen   (REH-goh-RA-feh-nib)
A drug used to treat colorectal cancer that has spread to other parts of the body and has not gotten better with other treatment. It is also used to treat gastrointestinal stromal tumors (GIST) that cannot be removed by surgery or have spread to other parts of the body and have not gotten better with other anticancer drugs. It is being studied in the treatment of other types of cancer. Regorafenib blocks the action of certain proteins, which may help keep cancer cells from growing and may kill them. It may also prevent the growth of new blood vessels that tumors need to grow. Regorafenib is a type of kinase inhibitor and a type of antiangiogenesis agent. Also called Stivarga.

regression    listen   (reh-GREH-shun)
A decrease in the size of a tumor or in the extent of cancer in the body.

regulatory T cell    listen   (REH-gyoo-luh-TOR-ee T sel)
A type of immune cell that blocks the actions of some other types of lymphocytes, to keep the immune system from becoming over-active. Regulatory T cells are being studied in the treatment of cancer. A regulatory T cell is a type of white blood cell and a type of lymphocyte. Also called suppressor T cell, T reg, and T-regulatory cell.

rehabilitation    listen   (REE-huh-BIH-lih-TAY-shun)
In medicine, a process to restore mental and/or physical abilities lost to injury or disease, in order to function in a normal or near-normal way.

rehabilitation specialist    listen   (REE-huh-BIH-lih-TAY-shun SPEH-shuh-list)
A healthcare professional who helps people recover from an illness or injury and return to daily life. Examples of rehabilitation specialists are physical therapists and occupational therapists.

relapse    listen   (REE-laps)
The return of a disease or the signs and symptoms of a disease after a period of improvement. Relapse also refers to returning to the use of an addictive substance or behavior, such as cigarette smoking.

relapse-free survival    listen   (REE-laps … ser-VY-vul)
In cancer, the length of time after primary treatment for a cancer ends that the patient survives without any signs or symptoms of that cancer. In a clinical trial, measuring the relapse-free survival is one way to see how well a new treatment works. Also called DFS, disease-free survival, and RFS.

relative odds    listen   (REH-luh-tiv …)
A measure of the odds of an event happening in one group compared to the odds of the same event happening in another group. In cancer research, relative odds are most often used in case-control (backward looking) studies to find out if being exposed to a certain substance or other factor increases the risk of cancer. For example, researchers may study a group of individuals with cancer (cases) and another group without cancer (controls) to see how many people in each group were exposed to a certain substance or factor. They calculate the odds of exposure in both groups and then compare the odds. A relative odds of one means that both groups had the same odds of exposure and, therefore, the exposure probably does not increase the risk of cancer. A relative odds of greater than one means that the exposure may increase the risk of cancer, and a relative odds of less than one means that the exposure may reduce the risk of cancer. Also called odds ratio.

relative risk    listen   (REH-luh-tiv …)
A measure of the risk of a certain event happening in one group compared to the risk of the same event happening in another group. In cancer research, relative risk is used in prospective (forward looking) studies, such as cohort studies and clinical trials. A relative risk of one means there is no difference between two groups in terms of their risk of cancer, based on whether or not they were exposed to a certain substance or factor, or how they responded to two treatments being compared. A relative risk of greater than one or of less than one usually means that being exposed to a certain substance or factor either increases (relative risk greater than one) or decreases (relative risk less than one) the risk of cancer, or that the treatments being compared do not have the same effects. Also called risk ratio.

relative survival rate    listen   (REH-luh-tiv ser-VY-vul …)
A way of comparing the survival of people who have a specific disease with those who don’t, over a certain period of time. This is usually five years from the date of diagnosis or the start of treatment for those with the disease. It is calculated by dividing the percentage of patients with the disease who are still alive at the end of the period of time by the percentage of people in the general population of the same sex and age who are alive at the end of the same time period. The relative survival rate shows whether the disease shortens life.

relaxation technique    listen   (ree-lak-SAY-shun tek-NEEK)
A method used to help reduce muscle tension and stress, lower blood pressure, and control pain. Examples of relaxation techniques include tensing and relaxing muscles throughout the body, guided imagery (focusing the mind on positive images), meditation (focusing thoughts), and deep breathing exercises.

relaxation therapy    listen   (ree-lak-SAY-shun THAYR-uh-pee)
A type of therapy that helps reduce muscle tension and stress, lowers blood pressure, and controls pain. It may involve tensing and relaxing muscles throughout the body. It may be used with guided imagery (focusing the mind on positive images) and meditation (focusing thoughts).

Relenza    listen   (reh-LEN-zuh)
A drug used to prevent and to treat influenza virus infections. It blocks the release of the virus from infected cells. It is a type of antiviral agent. Also called zanamivir.

religion    listen   (reh-LIH-jun)
A set of beliefs and practices that center on questions about the meaning of life and may involve the worship of a supreme being.

Relistor    listen   (REH-lih-stor)
A drug used to relieve certain side effects caused by treatment with opiods (pain killers similar to morphine), such as constipation (hard, dry stools), itching, and low urine flow. Relistor binds to opioid receptors outside the brain and may block the side effects of opioid drugs without affecting their ability to relieve pain. Relistor is a type of peripheral opioid receptor antagonist. Also called methylnaltrexone bromide.

REM sleep    listen   (… sleep)
One of the five stages of sleep. During REM sleep, the eyes move rapidly while closed and dreams occur. REM sleep is the lightest stage of sleep, during which a person may wake easily. During several hours of normal sleep, a person will go through several sleep cycles that include REM sleep and the 4 stages of non-REM (light to deep sleep). Also called rapid eye movement sleep.

Remeron    listen   (REH-meh-ron)
A drug used to treat depression. Remeron increases the levels of the chemicals serotonin and norepinephrine in the brain, which helps improve mood. It is a type of antidepressant. Also called mirtazapine.

remission    listen   (reh-MIH-shun)
A decrease in or disappearance of signs and symptoms of cancer. In partial remission, some, but not all, signs and symptoms of cancer have disappeared. In complete remission, all signs and symptoms of cancer have disappeared, although cancer still may be in the body.

remission induction therapy    listen   (reh-MIH-shun in-DUK-shun THAYR-uh-pee)
Initial treatment with anticancer drugs to decrease the signs or symptoms of cancer or make them disappear.

remote brachytherapy    listen   (ree-MOTE BRAY-kee-THAYR-uh-pee)
A type of internal radiation treatment in which the radioactive source is removed between treatments. Also called high-dose-rate remote brachytherapy and high-dose-rate remote radiation therapy.

renal artery    listen   (REE-nul AR-tuh-ree)
The main blood vessel that supplies blood to a kidney and its nearby adrenal gland and ureter. There is a renal artery for each kidney.

renal capsule    listen   (REE-nul KAP-sul)
The fibrous connective tissue that surrounds each kidney.

renal cell adenocarcinoma    listen   (REE-nul sel A-deh-noh-KAR-sih-NOH-muh)
The most common type of kidney cancer. It begins in the lining of the renal tubules in the kidney. The renal tubules filter the blood and produce urine. Also called hypernephroma, renal cell cancer, and renal cell carcinoma.

renal cell cancer    listen   (REE-nul sel KAN-ser)
The most common type of kidney cancer. It begins in the lining of the renal tubules in the kidney. The renal tubules filter the blood and produce urine. Also called hypernephroma, renal cell adenocarcinoma, and renal cell carcinoma.

renal cell carcinoma    listen   (REE-nul sel KAR-sih-NOH-muh)
The most common type of kidney cancer. It begins in the lining of the renal tubules in the kidney. The renal tubules filter the blood and produce urine. Also called hypernephroma, renal cell adenocarcinoma, and renal cell cancer.

renal collecting tubule    listen   (REE-nul kuh-LEK-ting TOO-byool)
The last part of a long, twisting tube that collects urine from the nephrons (cellular structures in the kidney that filter blood and form urine) and moves it into the renal pelvis and ureters. Also called collecting duct.

renal failure    listen   (REE-nul FAYL-yer)
A condition in which the kidneys stop working and are not able to remove waste and extra water from the blood or keep body chemicals in balance. Acute or severe renal failure happens suddenly (for example, after an injury) and may be treated and cured. Chronic renal failure develops over many years, may be caused by conditions like high blood pressure or diabetes, and cannot be cured. Chronic renal failure may lead to total and long-lasting renal failure, called end-stage renal disease (ESRD). A person in ESRD needs dialysis (the process of cleaning the blood by passing it through a membrane or filter) or a kidney transplant. Also called kidney failure.

renal fascia    listen   (REE-nul FA-shuh)
A fibrous envelope of tissue that surrounds the kidney. Also called Gerota's capsule and Gerota's fascia.

renal function    listen   (REE-nul FUNK-shun)
A term used to describe how well the kidneys work. The kidneys remove waste and extra water from the blood (as urine) and help keep chemicals (such as sodium, potassium, and calcium) balanced in the body. They also make hormones that help control blood pressure and stimulate bone marrow to make red blood cells. Also called kidney function.

renal function test    listen   (REE-nul FUNK-shun...)
A test in which blood or urine samples are checked for the amounts of certain substances released by the kidneys. A higher- or lower-than-normal amount of a substance can be a sign that the kidneys are not working the way they should. Also called kidney function test.

renal glomerulus    listen   (REE-nul gloh-MAYR-yoo-lus)
A tiny, round cluster of blood vessels within the kidneys. It filters the blood to reabsorb useful materials and remove waste as urine.

renal pelvis    listen   (REE-nul PEL-vus)
The area at the center of the kidney. Urine collects here and is funneled into the ureter, the tube that connects the kidney to the bladder.

renal tubular acidosis    listen   (REE-nul TOO-byoo-ler A-sih-DOH-sis)
A rare disorder in which structures in the kidney that filter the blood are impaired, producing urine that is more acid than normal.

Renova    listen   (ree-NOH-vuh)
A topical preparation of tretinoin that is used to treat acne. Tretinoin is a form of vitamin A.

replicate    listen   (REH-plih-kayt)
To make a copy or duplicate of something.

replication cycle    listen   (reh-plih-KAY-shun...)
In biology, refers to the reproduction cycle of viruses. A repliction cycle begins with the infection of a host cell and ends with the release of mature progeny virus particles.

reproductive cell    listen   (REE-proh-DUK-tiv sel)
An egg or sperm cell. Each mature reproductive cell carries a single set of 23 chromosomes.

reproductive medicine    listen   (REE-proh-DUK-tiv MEH-dih-sin)
A branch of medicine that specializes in fertility preservation, diagnosing and treating infertility, and other reproductive problems. Reproductive medicine also deals with issues related to puberty, menopause, contraception (birth control), and certain sexual problems.

reproductive system    listen   (REE-proh-DUK-tiv SIS-tem)
The organs involved in producing offspring. In women, this system includes the ovaries, the fallopian tubes, the uterus, the cervix, and the vagina. In men, it includes the prostate, the testes, and the penis.

rescue transplant    listen   (REH-skyoo TRANZ-plant)
A method of replacing blood-forming stem cells that were destroyed by treatment with high doses of anticancer drugs or radiation therapy. The stem cells help the bone marrow recover and make healthy blood cells. A rescue transplant may allow more chemotherapy or radiation therapy to be given so that more cancer cells are killed. It is usually done using the patient’s own stem cells that were saved before treatment. Also called stem cell rescue.

research base    listen   (reh-SERCH bays)
Refers to the institutions, clinical staff, and patients that can take part in a clinical trial.

research study    listen   (reh-SERCH STUH-dee)
A scientific study of nature that sometimes includes processes involved in health and disease. For example, clinical trials are research studies that involve people. These studies may be related to new ways to screen, prevent, diagnose, and treat disease. They may also study certain outcomes and certain groups of people by looking at data collected in the past or future.

resectable    listen   (ree-SEK-tuh-bul)
Able to be removed by surgery.

resected    listen   (ree-SEK-ted)
Removed by surgery.

resection    listen   (ree-SEK-shun)
Surgery to remove tissue or part or all of an organ.

resectoscope    listen   (ree-SEK-toh-skope)
A thin, tube-like instrument used to remove tissue from inside the body. A resectoscope has a light and lens for viewing. It also has a tool to remove tissue using an electrical current. It is inserted through the urethra to treat prostate disease in men and through the vagina and cervix to treat abnormal uterine bleeding in women.

residual disease    listen   (ree-ZID-yoo-ul dih-ZEEZ)
Cancer cells that remain after attempts to remove the cancer have been made.

resin    listen   (REH-zin)
A thick substance that comes from plants or can be made in the laboratory from certain chemicals. Resins do not dissolve in water, and are used in plastics, varnishes, printing inks, medicine, and to make fabrics stiff.

resiquimod    listen   (reh-SIH-kwih-mod)
A substance being studied in the treatment of some types of skin cancer. When put on the skin, resiquimod causes some immune cells to make certain chemicals that may help them kill tumor cells. It is also being studied to find out if adding it to a tumor vaccine improves the antitumor immune response. It is a type of imidazoquinoline and a type of immunomodulator.

resistant cancer    listen   (reh-ZIH-stunt KAN-ser)
Cancer that does not respond to treatment. The cancer may be resistant at the beginning of treatment, or it may become resistant during treatment. Also called refractory cancer.

resorption    listen   (ree-SORP-shun)
A process in which a substance, such as tissue, is lost by being destroyed and then absorbed by the body.

respirator    listen   (RES-pih-RAY-ter)
In medicine, a machine used to help a patient breathe. Also called ventilator.

respiratory disease    listen   (RES-pih-ruh-TOR-ee dih-ZEEZ)
A type of disease that affects the lungs and other parts of the respiratory system. Respiratory diseases may be caused by infection, by smoking tobacco, or by breathing in secondhand tobacco smoke, radon, asbestos, or other forms of air pollution. Respiratory diseases include asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, pneumonia, and lung cancer. Also called lung disorder and pulmonary disease.

respiratory syncytial virus    listen   (RES-pih-ruh-TOR-ee sin-SIH-shul VY-rus)
A virus that causes respiratory infections with cold-like symptoms. Also called RSV.

respiratory system    listen   (RES-pih-ruh-TOR-ee SIS-tem)
The organs that are involved in breathing. These include the nose, throat, larynx, trachea, bronchi, and lungs. Also called respiratory tract.

respiratory therapist    listen   (RES-pih-ruh-TOR-ee THAYR-uh-pist)
A health professional trained to evaluate and treat people who have breathing problems or other lung disorders.

respiratory therapy    listen   (RES-pih-ruh-TOR-ee THAYR-uh-pee)
Exercises and treatments that help improve or restore lung function.

respiratory tract    listen   (RES-pih-ruh-TOR-ee trakt)
The organs that are involved in breathing. These include the nose, throat, larynx, trachea, bronchi, and lungs. Also called respiratory system.

respite care    listen   (REH-spit kayr)
Temporary care given to a person who is unable to care for himself or herself so that the usual caregivers can have a break. Respite care may include in-home care, adult daycare, or nursing home care.

response    listen   (reh-SPONTS)
In medicine, an improvement related to treatment.

Response Evaluation Criteria In Solid Tumors    listen   (reh-SPONTS ee-VAL-yoo-AY-shun kry-TEER-ee-uh … SAH-lid TOO-mers)
A standard way to measure how well a cancer patient responds to treatment. It is based on whether tumors shrink, stay the same, or get bigger. To use Response Evaluation Criteria In Solid Tumors, there must be at least one tumor that can be measured on x-rays, CT scans, or MRI scans. The types of response a patient can have are a complete response (CR), a partial response (PR), progressive disease (PD), and stable disease (SD). Also called RECIST.

response rate    listen   (reh-SPONTS...)
The percentage of patients whose cancer shrinks or disappears after treatment.

resting    listen   (RES-ting)
In biology, refers to a cell that is not dividing.

restless legs syndrome    listen   (… SIN-drome)
A condition in which a person has a strong urge to move his or her legs in order to stop uncomfortable sensations. These include burning, itching, creeping, tugging, crawling, or pain. These feelings usually happen when a person is lying or sitting down, and are worse at night. They can also occur in other parts of the body. Also called RLS.

resveratrol    listen   (rez-VEER-uh-trol)
A substance found in the skins of grapes and in certain other plants, fruits, and seeds. It is made by various plants to help defend against invading fungi, stress, injury, infection, and too much sunlight. It is being studied in the prevention of cancer and heart disease. It is a type of antioxidant and a type of polyphenol.

retch    listen   (RECH)
The action of the stomach and esophagus to try to vomit (eject some or all of the contents of the stomach). Retching that does not cause vomiting is called dry heaves.

reticular dermis    listen   (reh-TIH-kyoo-ler DER-mis)
The thick bottom layer of the dermis (the inner layer of the skin). The reticular dermis has blood vessels and connective tissue that supports the skin. Hair follicles, oil and sweat glands, and other structures are also found in the reticular dermis.

Retin-A    listen   (REH-tin …)
A topical preparation of tretinoin that is used to treat acne. Tretinoin is a form of vitamin A.

Retin-A-Micro    listen   (REH-tin … MY-kroh)
A topical preparation of tretinoin that is used to treat acne. Tretinoin is a form of vitamin A.

retina    listen   (REH-tih-nuh)
The light-sensitive layers of nerve tissue at the back of the eye that receive images and sends them as electric signals through the optic nerve to the brain.

retinoblastoma    listen   (REH-tih-noh-blas-TOH-muh)
Cancer that forms in the tissues of the retina (the light-sensitive layers of nerve tissue at the back of the eye). Retinoblastoma usually occurs in children younger than 5 years. It may be hereditary or nonhereditary (sporadic).

retinoic acid    listen   (REH-tih-NOH-ik A-sid)
A nutrient that the body needs in small amounts to function and stay healthy. Retinoic acid is made in the body from vitamin A and helps cells to grow and develop, especially in the embryo. A form of retinoic acid made in the laboratory is put on the skin to treat conditions such as acne and is taken by mouth to treat acute promyelocytic leukemia (a fast-growing cancer in which there are too many immature blood-forming cells in the blood and bone marrow). Retinoic acid is being studied in the prevention and treatment of other types of cancer. Also called all-trans retinoic acid, ATRA, tretinoin, and vitamin A acid.

retinoid    listen   (REH-tih-noyd)
Vitamin A or a vitamin A-like compound.

retinol    listen   (REH-tih-nol)
A nutrient that the body needs in small amounts to function and stay healthy. Retinol helps in vision, bone growth, reproduction, growth of epithelium (cells that line the internal and external surfaces of the body), and fighting infections. It is fat-soluble (can dissolve in fats and oils). Retinol is found in liver, egg yolks, and whole milk dairy products from animals and in fish oils. It can also be made in the body from a substance found in some fruits and vegetables, such as cantaloupes, carrots, spinach, and sweet potatoes. Retinol is being studied in the prevention and treatment of some types of cancer. Also called vitamin A.

retinyl palmitate    listen   (REH-tih-nil PAL-mih-tayt)
A drug that is being studied in the prevention of cancer. It belongs to the family of drugs called retinoids.

retromolar trigone    listen   (reh-troh-MOH-ler TRY-gone)
The small area behind the wisdom teeth.

retroperitoneal    listen   (REH-troh-PAYR-ih-toh-NEE-ul)
Having to do with the area outside or behind the peritoneum (the tissue that lines the abdominal wall and covers most of the organs in the abdomen).

retropubic prostatectomy    listen   (reh-troh-PYOO-bik PROS-tuh-TEK-toh-mee)
Surgery to remove part or all of the prostate and some of the tissue around it. Nearby lymph nodes may also be removed. A retropubic prostatectomy may be done through an incision (cut) made in the wall of the lower abdomen, or it may be done using a laparoscope. A laparoscope is a thin, tube-like instrument with a light and lens for viewing. Several small incisions (cuts) are made in the wall of the abdomen, and the laparoscope is inserted through one opening to guide the surgery. Surgical instruments are inserted through the other openings to do the surgery.

retrospective    listen   (REH-troh-SPEK-tiv)
Looking back at events that have already taken place.

retrospective cohort study    listen   (REH-troh-SPEK-tiv KOH-hort STUH-dee)
A research study in which the medical records of groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke and those who do not smoke) are compared for a particular outcome (such as lung cancer). Also called historic cohort study.

retrospective study    listen   (REH-troh-SPEK-tiv STUH-dee)
A study that compares two groups of people: those with the disease or condition under study (cases) and a very similar group of people who do not have the disease or condition (controls). Researchers study the medical and lifestyle histories of the people in each group to learn what factors may be associated with the disease or condition. For example, one group may have been exposed to a particular substance that the other was not. Also called case-control study.

retroviral vector    listen   (REH-troh-VY-rul VEK-ter)
RNA from a virus that is used to insert genetic material into cells.

retrovirus    listen   (REH-troh-VY-rus)
A type of virus that has RNA instead of DNA as its genetic material. It uses an enzyme called reverse transcriptase to become part of the host cells’ DNA. This allows many copies of the virus to be made in the host cells. The virus that causes AIDS, the human immunodeficiency virus (HIV), is a type of retrovirus.

reverse transcription    listen   (ree-VERS tran-SKRIP-shun)
In biology, the process in cells by which an enzyme makes a copy of DNA from RNA. The enzyme that makes the DNA copy is called reverse transcriptase and is found in retroviruses, such as the human immunodeficiency virus (HIV). Reverse transcription can also be carried out in the laboratory.

ReVia    listen   (reh-VEE-uh)
A drug that blocks the action of opiates (drugs used to treat pain). It may be used in the treatment of intravenous opiate addiction or alcohol dependence. ReVia is also being studied in the treatment of breast cancer. It may block the effects of the hormone estrogen, which causes some breast cancer cells to grow, or block the blood flow to tumors. It is a type of opiate antagonist. Also called naltrexone, naltrexone hydrochloride, and Vivitrol.

Revlimid    listen   (REV-lih-mid)
A drug that is similar to thalidomide, and is used to treat multiple myeloma and certain types of anemia. It is also used to treat mantle cell lymphoma that has come back or has not gotten better after other treatment. It is being studied in the treatment of other conditions and types of cancer. Revlimid may help the immune system kill abnormal blood cells or cancer cells. It may also prevent the growth of new blood vessels that tumors need to grow. It is a type of antiangiogenesis agent and a type of immunomodulating agent. Also called CC-5013 and lenalidomide.

RevM10 gene    listen   (… jeen)
An antiviral gene that is being studied in the treatment of cancer in patients who have HIV, the virus that causes AIDS.

Reye syndrome    listen   (ray SIN-drome)
A rare disease that damages the brain and liver and causes death if not treated. It occurs most often in children younger than 15 years who have had a fever-causing virus, such as chickenpox or flu. Taking aspirin during a viral illness may increase the risk of Reye syndrome.

rF-TRICOM    listen  
A cancer vaccine made with a form of a chicken virus that does not cause disease in humans. It is being studied in the treatment of some types of cancer. The virus is changed in the laboratory to make human proteins that may help immune cells in the body kill tumor cells. Also called recombinant fowlpox-TRICOM vaccine.

RFS      
In cancer, the length of time after primary treatment for a cancer ends that the patient survives without any signs or symptoms of that cancer. In a clinical trial, measuring the RFS is one way to see how well a new treatment works. Also called DFS, disease-free survival, and relapse-free survival.

RFT5-dgA immunotoxin    listen   (... IH-myoo-noh-TOK-sin)
A monoclonal antibody linked to a toxic substance. It is being studied in the treatment of melanoma that has spread to distant parts of the body. RFT5-dgA immunotoxin is made in the laboratory. It can find and kill certain white blood cells that prevent the immune system from killing cancer cells. Also called IgG-RFT5-dgA.

RG7204      
A drug used to treat advanced melanoma that has a mutated (changed) form of a cell protein called BRAF. It is also being studied in the treatment of other types of cancer. RG7204 blocks this mutated protein, which may stop the growth of cancer cells. It is a type of kinase inhibitor and a type of targeted therapy agent. Also called BRAF (V600E) kinase inhibitor RO5185426, PLX4032, vemurafenib, and Zelboraf.

rhabdoid tumor    listen   (RAB-doyd TOO-mer)
A malignant tumor of either the central nervous system (CNS) or the kidney. Malignant rhabdoid tumors of the CNS often have an abnormality of chromosome 22. These tumors usually occur in children younger than 2 years.

rhabdomyosarcoma    listen   (RAB-doh-MY-oh-sar-KOH-muh)
Cancer that forms in the soft tissues in a type of muscle called striated muscle. Rhabdomyosarcoma can occur anywhere in the body.

rheumatism    listen   (ROO-muh-TIH-zum)
A group of disorders marked by inflammation or pain in the connective tissue structures of the body. These structures include bone, cartilage, and fat.

rheumatoid arthritis    listen   (ROO-muh-TOYD ar-THRY-tis)
An autoimmune disease that causes pain, swelling, and stiffness in the joints, and may cause severe joint damage, loss of function, and disability. The disease may last from months to a lifetime, and symptoms may improve and worsen over time.

Rheumatrex    listen   (ROO-muh-trex)
A drug used to treat some types of cancer, rheumatoid arthritis, and severe skin conditions, such as psoriasis. Rheumatrex stops cells from making DNA and may kill cancer cells. It is a type of antimetabolite. Also called amethopterin, methotrexate, and MTX.

rhIL-11      
A drug used to increase the number of blood cells, especially platelets, in some cancer patients receiving chemotherapy. rhIL-11 is a form of interleukin-11 (a cytokine normally made by support cells in the bone marrow) that is made in the laboratory. It is a type of biological response modifier. Also called Neumega, oprelvekin, and recombinant human interleukin-11.

rhinoscope    listen   (RY-noh-skope)
A thin, tube-like instrument used to examine the inside of the nose. A rhinoscope has a light and a lens for viewing and may have a tool to remove tissue. Also called nasoscope.

rhinoscopy    listen   (ry-NOS-koh-pee)
Examination of the inside of the nose using a rhinoscope. A rhinoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease. Also called nasoscopy.

rhizoxin    listen   (ry-ZOK-sin)
A substance that is being studied in the treatment of cancer. It comes from a fungus and is similar to vinca alkaloid drugs. It belongs to the family of drugs called antimitotic agents.

rhubarb    listen   (ROO-barb)
The root of this plant has been used in some cultures to treat certain medical problems. It may have anti-inflammatory and anticancer effects. The scientific name is Rheum palmatum or Rheum officinale. Also called Chinese rhubarb, da-huang, Indian rhubarb, and Turkish rhubarb.

ribavirin    listen   (RY-buh-VY-rin)
A drug used to treat respiratory syncytial virus (RSV) infection in the lungs.

riboflavin    listen   (RY-boh-FLAY-vin)
A nutrient in the vitamin B complex that the body needs in small amounts to function and stay healthy. Riboflavin helps make red blood cells, helps some enzymes work properly, and keeps skin, nails, and hair healthy. It is found in milk, eggs, malted barley, organ meats, yeast, and leafy vegetables. Riboflavin is water-soluble (can dissolve in water) and must be taken in every day. Not enough riboflavin can cause anemia (a low number of red blood cells), mouth sores, and skin problems. Amounts of riboflavin may be higher in the blood of patients with some types of cancer. Also called vitamin B2.

ribonucleic acid    listen   (RY-boh-noo-KLAY-ik A-sid)
One of two types of nucleic acid made by cells. Ribonucleic acid contains information that has been copied from DNA (the other type of nucleic acid). Cells make several different forms of ribonucleic acid, and each form has a specific job in the cell. Many forms of ribonucleic acid have functions related to making proteins. Ribonucleic acid is also the genetic material of some viruses instead of DNA. Ribonucleic acid can be made in the laboratory and used in research studies. Also called RNA.

ribonucleotide reductase inhibitor    listen   (RY-boh-NOO-klee-oh-tide ree-DUK-tays in-HIH-bih-ter)
A family of anticancer drugs that interfere with the growth of tumor cells by blocking the formation of deoxyribonucleotides (building blocks of DNA).

ribosome    listen   (RY-buh-some)
In biology, a structure found inside cells that is involved in making proteins. Ribosomes help link amino acids together to form proteins.

Richter syndrome    listen   (RIK-ter SIN-drome)
A rare condition in which chronic lymphocytic leukemia (CLL) changes into a fast-growing type of lymphoma. Symptoms of Richter syndrome include fever, loss of weight and muscle mass, and other health problems. Also called Richter transformation.

Richter transformation    listen   (RIK-ter TRANZ-for-MAY-shun)
A rare condition in which chronic lymphocytic leukemia (CLL) changes into a fast-growing type of lymphoma. Symptoms of Richter transformation include fever, loss of weight and muscle mass, and other health problems. Also called Richter syndrome.

rickets    listen   (RIH-kets)
A condition in children in which bones become soft and deformed because they don’t have enough calcium and phosphorus. It is caused by not having enough vitamin D in the diet or by not getting enough sunlight. In adults, this condition is called osteomalacia. Also called infantile rickets, juvenile rickets, and rachitis.

ridaforolimus    listen   (rih-duh-foh-ROH-lih-mus)
A substance being studied in the treatment of soft tissue and bone cancers. It is also being studied in the treatment of other solid tumors and hematologic cancer. Ridaforolimus stops cells from dividing and may cause cancer cells to die. It is a type of mTOR inhibitor. Also called AP23573.

rifabutin    listen   (RIH-fuh-BYOO-tin)
A drug used to prevent the spread of a bacterium called in patients with advanced HIV (the virus that causes AIDS) infection. It blocks an enzyme that the bacteria need to grow. It is a type of antibiotic. Also called Mycobutin.

rifampin    listen   (rih-FAM-pin)
A drug used in the treatment of infections caused by bacteria. It belongs to the family of drugs called antibiotics.

Rilutek    listen   (RIL-yoo-tek)
A drug used to treat a nerve disease called amyotrophic lateral sclerosis (ALS). It is also being studied in the treatment of melanoma (a type of skin cancer). Rilutek blocks the release of a substance that melanoma cells need to grow. It is a type of glutamate release inhibitor. Also called riluzole.

riluzole    listen   (RIL-yoo-zole)
A drug used to treat a nerve disease called amyotrophic lateral sclerosis (ALS). It is also being studied in the treatment of melanoma (a type of skin cancer). Riluzole blocks the release of a substance that melanoma cells need to grow. It is a type of glutamate release inhibitor. Also called Rilutek.

risedronate    listen   (rih-SEH-droh-nayt)
A substance that is being studied in the prevention and treatment of osteoporosis. It belongs to the family of drugs called bone resorption inhibitors.

risk assessment    listen   (… uh-SES-ment)
A process used to estimate the risk that a certain event will happen. In medicine, this may include a person’s risk of having a child with a certain condition or disease, such as cancer. It may also be used to estimate the risk of carrying a certain gene mutation (change), or of having an adverse event (unexpected medical problem) in response to certain types of drugs or other substances. A risk assessment may be done by collecting information about a person’s age, sex, personal and family medical history, ethnic background, lifestyle, and other factors and using statistics tools to calculate risk.

risk factor    listen   (... FAK-ter)
Something that increases the chance of developing a disease. Some examples of risk factors for cancer are age, a family history of certain cancers, use of tobacco products, being exposed to radiation or certain chemicals, infection with certain viruses or bacteria, and certain genetic changes.

risk group    listen   (risk groop)
In medicine, risk groups are used to describe people who are alike in important ways. For example, patients with the same type of cancer may be divided into different risk groups that depend on certain aspects of their disease. These risk groups may be based on the patients’ chance of being cured (good versus poor) or the chance that their disease will come back (high versus low). Treatment may be based on which risk group a patient falls into. Risk groups can also be used to describe people who share traits and behaviors that affect their chance of developing a disease. For example, people who do not smoke are in a lower risk group for lung cancer than people who smoke.

risk ratio    listen   (… RAY-shee-oh)
A measure of the risk of a certain event happening in one group compared to the risk of the same event happening in another group. In cancer research, risk ratios are used in prospective (forward looking) studies, such as cohort studies and clinical trials. A risk ratio of one means there is no difference between two groups in terms of their risk of cancer, based on whether or not they were exposed to a certain substance or factor, or how they responded to two treatments being compared. A risk ratio of greater than one or of less than one usually means that being exposed to a certain substance or factor either increases (risk ratio greater than one) or decreases (risk ratio less than one) the risk of cancer, or that the treatments being compared do not have the same effects. Also called relative risk.

Risperdal    listen   (RIS-per-dal)
A drug used to treat certain mental disorders, such as schizophrenia and bipolar disease. It may also be used to treat certain behavior problems in children. Risperdal blocks the action of certain chemicals in the brain. It is a type of antipsychotic. Also called risperidone.

risperidone    listen   (ris-PAYR-ih-done)
A drug used to treat certain mental disorders, such as schizophrenia and bipolar disease. It may also be used to treat certain behavior problems in children. Risperidone blocks the action of certain chemicals in the brain. It is a type of antipsychotic. Also called Risperdal.

Ritalin    listen   (RIH-tuh-lin)
A drug used to treat certain behavior disorders, such as attention deficit hyperactivity disorder (ADHD). It is also being studied as a way to improve brain function in patients treated with anticancer drugs. Ritalin acts on certain parts of the brain. It is a type of central nervous system stimulant. Also called Concerta and methylphenidate hydrochloride.

ritonavir    listen   (ry-TOH-nuh-veer)
A drug used to treat infection with HIV (the virus that causes AIDS). It is also being studied in the treatment of some types of cancer. Ritonavir blocks the ability of HIV to make copies of itself and may block the growth of cancer cells. It is a type of anti-HIV agent and a type of protease inhibitor. Also called Norvir.

ritual    listen   (RIH-chuh-wul)
An action or series of actions that is repeated, often in a religious or social setting. In medicine, it may describe a repeated action (such as hand washing) done to relieve feelings of fear, dread, and uneasiness in people who have an obsessive-compulsive disorder.

Rituxan    listen   (rih-TUK-sun)
A drug used to treat certain types of B-cell non-Hodgkin lymphoma. It is also used with other drugs to treat chronic lymphocytic leukemia and rheumatoid arthritis. It is being studied in the treatment of other types of cancer and other conditions. Rituxan binds to a protein called CD20, which is found on B-cells, and may kill cancer cells. It is a type of monoclonal antibody. Also called rituximab.

rituximab    listen   (rih-TUK-sih-mab)
A drug used to treat certain types of B-cell non-Hodgkin lymphoma. It is also used with other drugs to treat chronic lymphocytic leukemia and rheumatoid arthritis. It is being studied in the treatment of other types of cancer and other conditions. Rituximab binds to a protein called CD20, which is found on B-cells, and may kill cancer cells. It is a type of monoclonal antibody. Also called Rituxan.

RK-0202      
A substance that is being studied in the prevention of oral mucositis in patients receiving radiation therapy or chemotherapy for head and neck cancer.

RLS      
A condition in which a person has a strong urge to move his or her legs in order to stop uncomfortable sensations. These include burning, itching, creeping, tugging, crawling, or pain. These feelings usually happen when a person is lying or sitting down, and are worse at night. They can also occur in other parts of the body. Also called restless legs syndrome.

RMP-7      
A substance that is being studied for its ability to help other drugs reach the brain. It belongs to the family of drugs called bradykinin agonists. Also called lobradimil.

RNA      
One of two types of nucleic acid made by cells. RNA contains information that has been copied from DNA (the other type of nucleic acid). Cells make several different forms of RNA, and each form has a specific job in the cell. Many forms of RNA have functions related to making proteins. RNA is also the genetic material of some viruses instead of DNA. RNA can be made in the laboratory and used in research studies. Also called ribonucleic acid.

Ro 31-7453      
A substance that is being studied in the treatment of cancer. It may prevent cancer cells from dividing. It belongs to the family of drugs called cell cycle inhibitors.

Ro 50-3821      
A substance that is being studied in the treatment of anemia in patients who are receiving chemotherapy. It is a form of erythropoietin (a substance produced in the kidneys that stimulates the production of red blood cells) that has been changed in the laboratory. Also called methoxypolyethylene glycol epoetin beta.

RO4929097      
A substance being studied in the treatment of cancer. It blocks certain enzymes that are needed for cell growth. This may slow the growth of cancer cells. It may also decrease the growth of new blood vessels that tumors need to grow. It is a type of gamma-secretase inhibitor and a type of Notch signaling inhibitor.

rofecoxib    listen   (ROH-feh-KOK-sib)
A drug that was being used for pain relief and was being studied for its ability to prevent cancer and to prevent the growth of new blood vessels that tumors need to grow. It is a type of nonsteroidal anti-inflammatory drug and a type of antiangiogenesis agent. Rofecoxib was taken off the market in the U.S. because of safety concerns. Also called Vioxx.

Roman chamomile    listen   (ROH-mun KA-muh-mile)
A type of chamomile plant with daisy-like white flowers that is found in Europe, North America, and Argentina. The dried flowers are used in teas to calm and relax, to improve sleep, and to help with stomach problems. Its essential oil (scented liquid taken from plants) is used in perfumes, shampoos, face creams, lotions, and aromatherapy. The scientific names are Chamaemelum nobile and Anthemis nobilis. Also called English chamomile.

romidepsin    listen   (ROH-mih-DEP-sin)
A drug used to treat cutaneous T-cell lymphoma in patients who have been treated with other anticancer drugs. It is also being studied in the treatment of other types of cancer. Romidepsin blocks certain enzymes, which may help kill cancer cells. It is a type of depsipeptide and a type of histone deacetylase inhibitor. Also called FR901228 and Istodax.

romiplostim    listen   (ROH-mih-PLOH-stim)
A drug used to treat patients with immune thrombocytopenic purpura (ITP) who do not get better with other forms of treatment. In ITP, platelets (cells that cause blood clots to form) are destroyed by the immune system. Romiplostim is being studied as a way to treat low platelet counts caused by chemotherapy. It binds to the thrombopoietin receptor and causes the bone marrow to make more platelets. Romiplostim is also being studied in the treatment of myelodysplastic syndromes (a group of diseases in which the bone marrow does not make enough healthy blood cells). It is a type of thrombopoietin agonist. Also called AMG 531 and Nplate.

ropivacaine    listen   (roh-PIH-vuh-kayn)
A drug used to control pain and to cause a temporary loss of feeling in one part of the body, during and after surgery. It is also being studied for pain control after cancer surgery. It is a type of local anesthetic. Also called Naropin and ropivacaine hydrochloride.

ropivacaine hydrochloride    listen   (roh-PIH-vuh-kayn HY-droh-KLOR-ide)
A drug used to control pain and to cause a temporary loss of feeling in one part of the body, during and after surgery. It is also being studied for pain control after cancer surgery. It is a type of local anesthetic. Also called Naropin and ropivacaine.

rosiglitazone    listen   (roh-sig-LIH-tuh-zone)
The active ingredient in a drug that helps control the amount of glucose (sugar) in the blood and is being studied in the prevention and treatment of some types of cancer. Rosiglitazone stops cells from growing and may prevent the growth of new blood vessels that tumors need to grow. It is a type of thiazolidinedione and a type of antiangiogenesis agent.

rosiglitazone maleate    listen   (roh-sig-LIH-tuh-zone MAY-lee-AYT)
A drug that helps control the amount of glucose (sugar) in the blood and is being studied in the prevention and treatment of some types of cancer. Rosiglitazone maleate stops cells from growing and may prevent the growth of new blood vessels that tumors need to grow. It is a type of thiazolidinedione and a type of antiangiogenesis agent. Also called Avandia.

rosuvastatin calcium    listen   (roh-SOO-vuh-STA-tin KAL-see-um)
A drug used to lower the amount of cholesterol and other harmful substances, such as triglycerides, in the blood. It is also being studied in the prevention and treatment of some types of cancer and other conditions. Rosuvastatin calcium blocks an enzyme that helps make cholesterol in the body and it helps break down cholesterol. It also may cause cancer cells to die and may inhibit the growth of blood vessels that cancer cells need to grow. It is a type of HMG-CoA reductase inhibitor and a type of statin. Also called Crestor.

Roswell Park regimen    listen   (ROZ-wel … REH-jih-men)
A chemotherapy combination used to treat colorectal cancer. It is also used with radiation therapy to treat esophageal cancer and stomach cancer. It includes the drugs fluorouracil and leucovorin calcium.

rotationplasty    listen   (roh-TAY-shun-PLAS-tee)
Surgery used to remove a tumor in or near the knee joint, often in young people who are still growing. The knee and part of the thigh are removed. The part of the leg that remains below the knee is then attached to the part of the leg above the knee, with the foot facing backward and the ankle joint acting as a new knee. The patient is then fitted with an artificial lower leg and foot.

Rothmund-Thomson syndrome    listen   (ROT-moond-TOM-sun SIN-drome)
A rare inherited disorder that affects the skin and many other parts of the body, including the bones, eyes, nose, hair, nails, teeth, testes, and ovaries. People with Rothmund-Thomson syndrome have an increased risk of osteosarcoma (bone cancer). Also called RTS.

RPI.4610      
A substance being studied in the treatment of cancer. RPI.4610 is a special type of RNA made in the laboratory. It stops a protein called vascular endothelial growth factor receptor (VEGFR) from being made. This may prevent the growth of new blood vessels that tumors need to grow. It is a type of angiogenesis inhibitor and a type of ribozyme. Also called Angiozyme.

RPR 109881A      
A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called taxanes.

RSR13      
A substance being studied in the treatment of brain tumors and some other types of cancer. It increases the amount of oxygen in tumor tissues, which may make the tumor cells easier to kill with radiation therapy. RSR13 is a type of radiosensitizing agent. Also called efaproxiral.

RSV      
A virus that causes respiratory infections with cold-like symptoms. Also called respiratory syncytial virus.

RTA 744      
A substance being studied in the treatment of adult brain tumors. RTA 744 crosses the blood-brain barrier and blocks an enzyme needed for cancer growth. It is a type of topoisomerase inhibitor. Also called topoisomerase II inhibitor RTA 744.

RTS      
A rare inherited disorder that affects the skin and many other parts of the body, including the bones, eyes, nose, hair, nails, teeth, testes, and ovaries. People with RTS have an increased risk of osteosarcoma (bone cancer). Also called Rothmund-Thomson syndrome.

RU 486      
A drug used to end early pregnancies. It is also being studied in the treatment of some types of cancer and other conditions. RU 486 blocks the action of progesterone, a hormone that helps some cancers grow. It is a type of antiprogesterone. Also called Mifeprex and mifepristone.

ruxolitinib phosphate    listen   (RUK-soh-LIH-tih-nib FOS-fayt)
A drug used to treat polycythemia vera in patients who cannot be treated with or have not gotten better with hydroxyurea. It is also used to treat certain types of myelofibrosis. It is being studied in the treatment of other blood diseases and some types of cancer. Ruxolitinib phosphate blocks a protein called JAK, which may help keep abnormal blood cells or cancer cells from growing. It is a type of tyrosine kinase inhibitor. Also called Jakafi.

rV-TRICOM    listen  
A cancer vaccine made with a form of a vaccinia virus that does not cause disease in humans. It is being studied in the treatment of some types of cancer. The virus is changed in the laboratory to make human proteins that may help immune cells in the body kill tumor cells. Also called recombinant vaccinia-TRICOM vaccine and vaccinia-TRICOM vaccine.

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