NCI Dictionary of Cancer Terms

246 results found for: O

O(6)-benzylguanine: (… BEN-zul-GWAH-neen); A drug that may improve the response of cancer cells to chemotherapy.
oat cell cancer: (... sel KAN-ser); A fast-growing type of cancer that usually occurs in the lungs but may also occur in many other parts of the body, such as the cervix, ovary, bladder, prostate, liver, pancreas, and stomach. These cancer cells usually look like small, oval-shaped oats when viewed under a microscope. Oat cell cancer tends to spread quickly to other parts of the body and usually has a poor prognosis (chance of recovery). Also called small cell carcinoma.
ob/gyn: A branch of medicine that specializes in the care of women during pregnancy and childbirth and in the diagnosis and treatment of diseases of the female reproductive organs. It also specializes in other women’s health issues, such as menopause, hormone problems, contraception (birth control), and infertility. Also called obstetrics and gynecology.
obatoclax mesylate: (oh-BA-toh-klax MEH-zih-layt); A substance being studied in the treatment of several types of cancer. It is a form of obatoclax, which blocks the activity of certain proteins needed for cells to live and may cause tumor cells to die. It is a type of apoptosis inducer.
obecabtagene autoleucel: (OH-beh-KAB-tuh-jeen AW-toh-LOO-sel); A drug used to treat adults with acute lymphoblastic leukemia that came back or did not get better during or after other treatment. It is also being studied in the treatment of other conditions and types of cancer. Obecabtagene autoleucel is made using a patient’s T cells (a type of immune system cell). A gene for a special receptor called chimeric antigen receptor (CAR) is added to the T cells in the laboratory. These changed T cells called CAR T cells are grown in large numbers in the laboratory and given to the patient by infusion. Obecabtagene autoleucel binds to a protein called CD19, which is found on some leukemia cells. This helps the body’s immune system kill cancer cells. Obecabtagene autoleucel is a type of CAR T-cell therapy. Also called Aucatzyl.
obesity: (oh-BEE-sih-tee); A common, chronic disease marked by an abnormally high, unhealthy amount of body fat. Having obesity can lead to many health problems, including heart disease, stroke, high blood pressure, diabetes, sleep apnea, arthritis, kidney disease, and certain types of cancer.
obinutuzumab: (OH-bin-yoo-TOO-zoo-mab); A drug used with other drugs to treat certain types of follicular lymphoma and chronic lymphocytic leukemia. It is also being studied in the treatment of other types of cancer. Obinutuzumab binds to a protein called CD20, which is found on B cells (a type of white blood cell) and some types of leukemia and lymphoma cells. Obinutuzumab may block CD20 and help the immune system kill cancer cells. It is a type of monoclonal antibody. Also called Gazyva.
objective improvement: (ub-JEK-tiv im-PROOV-ment); An improvement that can be measured by the health care provider (for example, when a tumor shrinks or there are fewer cancer cells in the blood).
objective response: (ub-JEK-tiv reh-SPONTS); A measurable response.
objective response rate: (ub-JEK-tiv reh-SPONTS rayt); The percentage of people in a study or treatment group who have a partial response or complete response to the treatment within a certain period of time. A partial response is a decrease in the size of a tumor or in the amount of cancer in the body, and a complete response is the disappearance of all signs of cancer in the body. In a clinical trial, measuring the objective response rate is one way to see how well a new treatment works. Also called ORR.
oblimersen sodium: (oh-blih-MER-sen SOH-dee-um); A substance being studied in the treatment of cancer. It may kill cancer cells by blocking the production of a protein that makes cancer cells live longer and by making them more sensitive to anticancer drugs. It is a type of antisense oligodeoxyribonucleotide. Also called augmerosen, bcl-2 antisense oligodeoxynucleotide G3139, and Genasense.
observation: (OB-ser-VAY-shun); In medicine, watching a patient’s condition but not giving treatment unless symptoms appear or change.
observational study: (OB-ser-VAY-shuh-nul STUH-dee); A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given).
obsessive-compulsive disorder: (ob-SEH-siv-kum-PUL-siv dis-OR-der); An anxiety disorder in which a person has intrusive ideas, thoughts, or images that occur repeatedly, and in which he or she feels driven to perform certain behaviors over and over again. For example, a person may worry all the time about germs and so will wash his or her hands over and over again. Having an obsessive-compulsive disorder may cause a person to have trouble carrying out daily activities.
obstetrician: (OB-steh-TRIH-shun); A doctor who specializes in caring for women during pregnancy and childbirth. Obstetricians also care for the fetus (unborn baby), treat problems with pregnancy, and deliver babies.
obstetrics and gynecology: (ob-STEH-trix ... GY-neh-KAH-loh-jee); A branch of medicine that specializes in the care of women during pregnancy and childbirth and in the diagnosis and treatment of diseases of the female reproductive organs. It also specializes in other women’s health issues, such as menopause, hormone problems, contraception (birth control), and infertility. Also called ob/gyn.
obstruction: (ub-STRUK-shun); Blockage of a passageway.
obtundation: (ob-tun-DAY-shun); A dulled or reduced level of alertness or consciousness.
OCA: A group of rare, inherited disorders in which the skin, hair, and eyes have little or no melanin (pigment). Most people with these disorders have very pale skin, white or light-colored hair, and light-colored eyes. People with OCA can also have vision problems, including blurry vision, rapid eye movement, crossed eyes, and increased sensitivity to light. People with these disorders have a high risk of developing squamous cell skin cancer at a very early age. The seven types of OCA are caused by mutations (changes) in the TYR, OCA2, TYRP1, SLC45A2, OCA5, SLC24A5, or C10orf11 gene. These genes are involved in making melanin. The amount of skin, hair, and eye pigment seen in each OCA type depends on the gene and mutation involved. Also called oculocutaneous albinism.
OCA2 gene: (... jeen); A gene that makes a protein thought to be involved in making melanin (a pigment that gives color to the skin, hair, and eyes). Mutations (changes) in the OCA2 gene have been found in an inherited condition called oculocutaneous albinism. People with this condition have very pale skin and light-colored hair and eyes. They also have a high risk of developing skin cancer at an early age.
occult primary tumor: (uh-KULT PRY-mayr-ee TOO-mer); Cancer in which the site of the primary (original) tumor cannot be found. Most metastases from occult primary tumors are found in the head and neck.
occult stage non-small cell lung cancer: (uh-KULT ... sel lung KAN-ser); Cancer cannot be seen by imaging or bronchoscopy. Cancer cells are found in sputum or bronchial washings (a sample of cells taken from inside the airways that lead to the lungs). Cancer may have spread to other parts of the body.
occupational therapist: (AH-kyoo-PAY-shuh-nul THAYR-uh-pist); A health professional trained to help people who are ill or disabled learn to manage their daily activities.
OCT: A procedure that uses infrared light waves to give three-dimensional (3-D) pictures of structures inside tissues and organs. The pictures are made by a computer linked to the light source. Also called optical coherence tomography.
octreotide: (ok-TREE-oh-tide); A drug similar to the naturally occurring growth hormone inhibitor somatostatin. Octreotide is used to treat diarrhea and flushing associated with certain types of tumors.
octreotide scan: (ok-TREE-oh-tide skan); A type of radionuclide scan used to find carcinoid and other types of tumors. Radioactive octreotide, a drug similar to somatostatin, is injected into a vein and travels through the bloodstream. The radioactive octreotide attaches to tumor cells that have receptors for somatostatin. A radiation-measuring device detects the radioactive octreotide, and makes pictures showing where the tumor cells are in the body. Also called somatostatin receptor scintigraphy and SRS.
oculocutaneous albinism: (AH-kyoo-loh-kyoo-TAY-nee-us AL-bih-NIH-zum); A group of rare, inherited disorders in which the skin, hair, and eyes have little or no melanin (pigment). Most people with these disorders have very pale skin, white or light-colored hair, and light-colored eyes. People with oculocutaneous albinism can also have vision problems, including blurry vision, rapid eye movement, crossed eyes, and increased sensitivity to light. People with these disorders have a high risk of developing squamous cell skin cancer at a very early age. The seven types of oculocutaneous albinism are caused by mutations (changes) in the TYR, OCA2, TYRP1, SLC45A2, OCA5, SLC24A5, or C10orf11 gene. These genes are involved in making melanin. The amount of skin, hair, and eye pigment seen in each oculocutaneous albinism type depends on the gene and mutation involved. Also called OCA.
oculodermal melanocytosis: (AH-kyoo-loh-DER-mul meh-LAN-oh-sy-TOH-sis); A condition marked by brown, blue, or gray patches, usually on the inside of the eye and on the skin near or around the eye. It may also affect the eyelid and mouth. It is caused by an increase in the number of cells called melanocytes in skin and eye tissue. Melanocytes make a substance called melanin, which gives color to skin and eyes. Having oculodermal melanocytosis may increase the risk of glaucoma and a type of eye cancer called intraocular melanoma. Also called nevus of Ota.
odds ratio: (… RAY-shee-oh); 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, odds ratios 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. An odds ratio of one means that both groups had the same odds of exposure and, therefore, the exposure probably does not increase the risk of cancer. An odds ratio of greater than one means that the exposure may increase the risk of cancer, and an odds ratio of less than one means that the exposure may reduce the risk of cancer. Also called relative odds.
Odomzo: (oh-DOM-zoh); A drug used to treat locally advanced basal cell carcinoma (BCC) that has come back after surgery or radiation therapy. It is also used in patients who cannot be treated with surgery or radiation therapy. Odomzo is also being studied in the treatment of other types of cancer. Odomzo blocks a type of protein involved in tissue growth and repair and may block the growth of cancer cells. It is a type of hedgehog signaling pathway antagonist. Also called erismodegib, LDE225, and sonidegib phosphate.
odor: (OH-der); A smell.
odorant: (OH-deh-runt); A substance that gives off a smell.
OED: The presence of abnormal cells in the tissues of the mouth. These tissues include the lips, the lining of the inside of the cheeks, the gums, the front two thirds of the tongue, the bottom of the mouth under the tongue, the bony part of the roof of the mouth, and the small area behind the wisdom teeth. OED may be found in patches of tissue that look red, white, or a mixture of both colors but can only be diagnosed by looking at the cells under a microscope. It is most commonly caused by tobacco or alcohol use. It may also be caused by infection with certain types of human papillomavirus (HPV). OED is not cancer but may become cancer and spread to nearby normal tissue. It can be mild, moderate, or severe, depending on how abnormal the cells look under a microscope and how much of the tissues in the mouth are affected. Also called oral dysplasia and oral epithelial dysplasia.
OEPA: An abbreviation for a chemotherapy combination that is often used with radiation therapy to treat a certain type of childhood Hodgkin lymphoma in males. It includes the drugs vincristine sulfate (Oncovin), etoposide, prednisone, and doxorubicin hydrochloride (Adriamycin). Also called OEPA regimen.
OEPA regimen: (… REH-jih-men); An abbreviation for a chemotherapy combination that is often used with radiation therapy to treat a certain type of childhood Hodgkin lymphoma in males. It includes the drugs vincristine sulfate (Oncovin), etoposide, prednisone, and doxorubicin hydrochloride (Adriamycin). Also called OEPA.
ofatumumab: (OH-fa-TOO-moo-mab); A drug used alone or with other drugs to treat certain types of chronic lymphocytic leukemia. It is also being studied in the treatment of other types of cancer. Ofatumumab binds to a protein called CD20, which is found on B cells (a type of white blood cell) and some types of leukemia and lymphoma cells. Ofatumumab may block CD20 and help the immune system kill cancer cells. It is a type of monoclonal antibody. Also called Arzerra and HuMax-CD20.
OFF: An abbreviation for a chemotherapy combination used to treat pancreatic cancer. It includes the drugs oxaliplatin, fluorouracil, and leucovorin (folinic acid). Also called OFF regimen.
OFF regimen: (… REH-jih-men); An abbreviation for a chemotherapy combination used to treat pancreatic cancer. It includes the drugs oxaliplatin, fluorouracil, and leucovorin (folinic acid). Also called OFF.
off-label: (... LAY-bel); Describes the legal use of a prescription drug to treat a disease or condition for which the drug has not been approved by the U.S. Food and Drug Administration.
off-target effect: (… TAR-get eh-FEKT); Describes the effects that can occur when a drug binds to targets (proteins or other molecules in the body) other than those for which the drug was meant to bind. This can lead to unexpected side effects that may be harmful. Learning about the off-target effects of drugs may help in drug development.
Office for Human Research Protections: (AH-fis … HYOO-mun REE-serch proh-TEK-shuns); The office within the U.S. Department of Health and Human Services (DHHS) that protects the rights, welfare, and well-being of people involved in clinical trials. It also makes sure that the research follows the law 45 CFR 46 (Protection of Human Subjects). Also called OHRP.
ofloxacin: (oh-FLOK-suh-sin); An antibiotic drug used to treat infection. It belongs to the family of drugs called quinolone antibiotics.
OGF: A substance that relieves pain and is being studied in the treatment of some types of cancer. OGFs bind to cells in the body, including tumor cells, which have OGF receptors on the surface. This may help stop the growth of the tumor cells. It may also prevent the growth of blood vessels that tumors need to grow. An OGF is a type of biological response modifier and a type of antiangiogenesis agent. Also called opioid growth factor.
Ogivri: (oh-GIV-ree); A drug used alone or with other drugs to treat certain types of breast cancer, stomach cancer, and gastroesophageal junction cancer that are HER2 positive. It is also being studied in the treatment of other types of cancer. Ogivri binds to a protein called HER2, which is found on some cancer cells. This may help the immune system kill cancer cells. Ogivri is a type of monoclonal antibody and a type of HER2 receptor antagonist. Also called Herceptin, Hercessi, Herzuma, Kanjinti, Ontruzant, trastuzumab, and Trazimera.
Ogsiveo: (og-SIH-vee-oh); A drug used to treat adults with desmoid tumors (a type of soft tissue tumor) that have gotten worse and need systemic therapy. It is also being studied in the treatment of other types of cancer. Ogsiveo binds to a protein called gamma secretase, which blocks the activation of other proteins called Notch receptors. Blocking these proteins may help keep tumor cells from growing and may kill them. Ogsiveo is a type of gamma secretase inhibitor. Also called nirogacestat hydrobromide.
OGX-011: A substance being studied in the treatment of cancer. It blocks the production of a protein called clusterin, which helps cells live longer. This may kill cancer cells that need clusterin to grow. It may also make cells more sensitive to anticancer drugs. It is a type of antisense oligonucleotide, and a type of chemosensitizing agent. Also called custirsen sodium.
OHRP: The office within the U.S. Department of Health and Human Services (DHHS) that protects the rights, welfare, and well-being of people involved in clinical trials. It also makes sure that the research follows the law 45 CFR 46 (Protection of Human Subjects). Also called Office for Human Research Protections.
ointment: (OYNT-ment); A substance used on the skin to soothe or heal wounds, burns, rashes, scrapes, or other skin problems. Also called unguent.
Ojemda: (oh-JEM-dah); A drug used to treat children aged 6 months and older with low-grade glioma (a type of brain tumor) that has certain mutations (changes) in the BRAF gene. It is used in patients whose tumor came back or did not get better after treatment with other therapy. It is also being studied in the treatment of other types of cancer. Ojemda blocks certain proteins made by the mutated BRAF gene, which may help keep tumor cells from growing. It is a type of kinase inhibitor. Also called tovorafenib.
Ojjaara: (oh-JAR-uh); A drug used to treat intermediate-risk or high-risk myelofibrosis (MF), including primary MF, post-polycythemia vera MF, and post-essential thrombocythemia MF, in adults with anemia. Ojjaara blocks JAK and other proteins, which may help keep abnormal blood cells or cancer cells from growing. It is a type of kinase inhibitor. Also called momelotinib dihydrochloride monohydrate.
olanzapine: (oh-LAN-zuh-peen); A drug used to treat certain mental disorders. It is also being studied in the treatment of nausea and vomiting caused by some cancer treatments. It is a type of antipsychotic and a type of monoamine antagonist. Also called Zyprexa and Zyprexa Zydis.
olaparib: (oh-LA-puh-rib); A drug used alone or with other drugs to treat adults with certain types of prostate cancer, pancreatic cancer, breast cancer, or ovarian, fallopian tube, or primary peritoneal cancer. It is also being studied in the treatment of other types of cancer. Olaparib blocks an enzyme involved in many cell functions, including the repair of DNA damage. Blocking this enzyme may help keep cancer cells from repairing their damaged DNA, causing them to die. Olaparib is a type of PARP inhibitor. Also called AZD2281, Lynparza, and PARP inhibitor AZD2281.
Oleptro: (oh-LEP-troh); A drug used to treat depression. It may also be used to help relieve anxiety and insomnia (trouble sleeping) and to treat certain other disorders. Oleptro increases the level of the chemical serotonin in the brain, which helps improve mood. It is a type of antidepressant. Also called trazodone.
olfaction: (ol-FAK-shun); The sense of smell.
olfactory: (ol-FAK-tuh-ree); Having to do with the sense of smell.
olfactory bulb: (ol-FAK-tuh-ree bulb); A rounded mass of tissue that contains several types of nerve cells that are involved in the sense of smell. There are two olfactory bulbs on the bottom side of the brain, one above each nasal cavity. The olfactory bulbs receive information about smells from the nose and send it to the brain by way of the olfactory tracts.
olfactory neuroblastoma: (ol-FAK-tuh-ree NOOR-oh-blas-TOH-muh); A rare type of cancer that forms in the tissues of the upper part of the nasal cavity (space inside the nose). This area is near the bone that separates the nasal cavity from the brain. These tissues are involved in the sense of smell. Olfactory neuroblastoma may spread from the nasal cavity to the bone around the eyes, the sinuses, the front part of the brain, or the lymph nodes in the neck. It is the most common type of nasal cavity tumor in children, especially in teens. Also called esthesioneuroblastoma.
olfactory system: (ol-FAK-tuh-ree SIS-tem); The parts of the body involved in sensing smell, including the nose and many parts of the brain. Smell may affect emotion, behavior, memory, and thought.
olfactory transduction: (ol-FAK-tuh-ree tranz-DUK-shun); A series of events in which cells in the nose bind to scent-bearing molecules and send electrical signals to the brain where they are perceived as smells.
oligoastrocytoma: (AH-lih-goh-AS-troh-sy-TOH-muh); A brain tumor that forms from both oligodendrocytes and astrocytes, which are types of glial cells (cells that cover and protect nerve cells in the brain and spinal cord and help them work the way they should). An oligoastrocytoma is a type of mixed glioma.
oligodendrocyte: (AH-lih-goh-DEN-droh-site); A cell that forms the myelin sheath (a layer that covers and protects nerve cells) in the brain and spinal cord. An oligodendrocyte is a type of glial cell.
oligodendroglial tumor: (AH-lih-goh-den-DROH-glee-ul TOO-mer); A rare, slow-growing tumor that begins in oligodendrocytes (cells that cover and protect nerve cells in the brain and spinal cord). Also called oligodendroglioma.
oligodendroglioma: (AH-lih-goh-DEN-droh-glee-OH-muh); A rare, slow-growing tumor that begins in oligodendrocytes (cells that cover and protect nerve cells in the brain and spinal cord). Also called oligodendroglial tumor.
oligofructose-enriched inulin: (AH-lih-goh-FROOK-tose-en-RICHT IN-yoo-lin); 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. Oligofructose-enriched inulin is made by combining two substances that occur naturally in many plants, including chicory root, wheat, bananas, onion, and garlic. Oligofructose-enriched inulin helps healthy bacteria grow in the intestines and helps the body absorb calcium and magnesium. Also called Raftilose Synergy 1.
oligometastasis: (AH-lih-goh-meh-TAS-tuh-sis); A type of metastasis in which cancer cells from the original (primary) tumor travel through the body and form a small number of new tumors (metastatic tumors) in one or two other parts of the body. For example, cancer cells may spread from the breast to form one or two new tumors in the brain or spread from the colon to form new tumors in the liver. These types of tumors may be treatable.
oligopolyposis: (AH-lih-goh-PAH-lee-POH-sis); The condition of having between 10 and 100 polyps (abnormal growths) on the inner walls of the colon and rectum. This occurs in people who have certain types of inherited colorectal cancer syndromes, such as AFAP.
Ollier disease: (oh-lee-AY dih-ZEEZ); A rare disorder that causes benign (not cancer) growths of cartilage in the bones that may become cancer. These growths, called enchondromas, usually occur in the bones of the hands and feet, but they may also occur in the skull, ribs, and spine. They may cause bones to break, to be deformed, or to be shorter than usual. People with Ollier disease have an increased risk of developing certain types of cancer, including chondrosarcoma (cancer that forms in bone cartilage) and cancers of the ovary or liver. Ollier disease is most common in children and young adults. Also called enchondromatosis.
oltipraz: (OL-tih-praz); A drug used in cancer prevention.
olutasidenib: (oh-LOO-tuh-SIH-deh-nib); A drug used to treat adults with acute myeloid leukemia that has come back or has not gotten better with other treatment and has a mutation (change) in the IDH1 gene. It is also being studied in the treatment of other types of cancer. Olutasidenib blocks the protein made by the mutated IDH1 gene. Blocking this protein may help keep cancer cells from growing. Olutasidenib is a type of enzyme inhibitor. Also called Rezlidhia.
omacetaxine mepesuccinate: (OH-mah-seh-TAK-seen MEH-peh-SUK-sih-nayt); A drug used to treat adults with certain types of chronic myelogenous leukemia that cannot be treated with tyrosine kinase inhibitors (a type of anticancer drug) or that have not gotten better after treatment with at least two tyrosine kinase inhibitors. It is also being studied in the treatment of other types of cancer. Omacetaxine mepesuccinate blocks certain proteins involved in cell growth and may kill cancer cells. It is a type of plant alkaloid and a type of protein synthesis inhibitor. Also called homoharringtonine and Synribo.
omega-3 fatty acid: (oh-MAY-guh-3 ...); A type of fat obtained in the diet and involved in immunity.
omentectomy: (OH-men-TEK-toh-mee); Surgery to remove part or all of the omentum.
omentum: (oh-MEN-tum); A fold of the peritoneum (the thin tissue that lines the abdomen) that surrounds the stomach and other organs in the abdomen.
omeprazole: (oh-MEH-pruh-zole); A drug that inhibits gastric acid secretion.
Ommaya reservoir: (oh-MY-uh REH-zer-vwahr); A device surgically placed under the scalp and used to deliver anticancer drugs to the fluid surrounding the brain and spinal cord.
ON 01910.Na: A substance being studied in the treatment of cancer. It blocks certain proteins that are needed for cell growth and may kill cancer cells. ON 01910.Na is a type of protein kinase inhibitor and a type of benzyl styryl sulfone analog.
onabotulinumtoxinA: (ON-uh-BAH-choo-LY-num-TOK-sin-A); A drug used to treat certain medical conditions. These include severe underarm sweating and severe muscle spasms in the neck and shoulders. OnabotulinumtoxinA is also used to smooth wrinkles on the face. It is being studied in the treatment of pain in patients with skin leiomyomas (benign smooth muscle tumors) and other conditions. It is a form of a toxin made by the bacterium Clostridium botulinum.
Oncaspar: (ON-kah-spar); A drug used with other drugs to treat adults and children with acute lymphoblastic leukemia. It is used in patients whose cancer has not already been treated or who cannot be treated with asparaginase. It is also being studied in the treatment of other types of cancer. Oncaspar is made up of the enzyme L-asparaginase that is linked to a substance called PEG, which makes the drug stay in the body longer. L-asparaginase comes from the bacterium E. coli and breaks down the amino acid asparagine. This may stop the growth of cancer cells that need asparagine to grow. Oncaspar is a type of protein synthesis inhibitor. Also called PEG-asparaginase and pegaspargase.
oncogene: (ON-koh-jeen); A mutated (changed) form of a type of gene called a proto-oncogene, which is involved in normal cell growth and division. When a proto-oncogene is changed so that too many copies are made or it becomes more active than normal, it is called an oncogene. Oncogenes may cause normal cells to become cancer cells and grow in the body. Mutations that lead to the conversion of proto-oncogenes to oncogenes usually occur during a person’s lifetime and are not inherited from a parent.
oncologist: (on-KAH-loh-jist); A doctor who has special training in diagnosing and treating cancer. Some oncologists specialize in a particular type of cancer treatment. For example, a radiation oncologist specializes in treating cancer with radiation.
oncology: (on-KAH-loh-jee); A branch of medicine that specializes in the diagnosis and treatment of cancer. It includes medical oncology (the use of chemotherapy, hormone therapy, and other drugs to treat cancer), radiation oncology (the use of radiation therapy to treat cancer), and surgical oncology (the use of surgery and other procedures to treat cancer).
oncology nurse: (on-KAH-loh-jee...); A nurse who specializes in treating and caring for people who have cancer.
oncology pharmacy specialist: (on-KAH-loh-jee FAR-muh-see SPEH-shuh-list); A licensed pharmacist with special training in how to design, give, monitor, and change chemotherapy for cancer patients. Also called BCOP and board certified oncology pharmacy specialist.
oncolysate: (on-KAH-lih-sayt); An extract made from cancer cells.
oncolysis: (on-KAH-lih-sis); The lysis (breakdown) of cancer cells. This can be caused by chemical or physical means (for example, strong detergents or high-energy sound waves) or by infection with a strain of virus that can lyse cells.
oncolytic virotherapy: (ON-koh-LIH-tik VY-roh-THAYR-uh-pee); Treatment using an oncolytic virus (a virus that infects and breaks down cancer cells but not normal cells ). Oncolytic virotherapy may make it easier to kill tumor cells with chemotherapy and radiation therapy. It is a type of targeted therapy. Also called oncolytic virus therapy, viral therapy, and virotherapy.
oncolytic virus: (ON-koh-LIH-tik VY-rus); A type of virus that infects and lyses (breaks down) cancer cells but not normal cells. Oncolytic viruses can occur naturally or can be made in the laboratory by changing other viruses. Certain oncolytic viruses are being studied in the treatment of cancer. They may make it easier to kill tumor cells with chemotherapy and radiation therapy.
oncolytic virus therapy: (ON-koh-LIH-tik VY-rus THAYR-uh-pee); Treatment using an oncolytic virus (a virus that infects and breaks down cancer cells but not normal cells ). Oncolytic virus therapy may make it easier to kill tumor cells with chemotherapy and radiation therapy. It is a type of targeted therapy. Also called oncolytic virotherapy, viral therapy, and virotherapy.
Onconase: (ON-koh-nays); A substance being studied in the treatment of cancer. It is a type of ribonuclease enzyme. Also called ranpirnase.
Oncophage: (ON-koh-fayj); A vaccine made from a patient’s tumor cells that may help the body’s immune system kill cancer cells. This vaccine is used to treat kidney cancer, a type of brain cancer called glioma, and metastatic melanoma (a type of skin cancer that has spread). It is also being studied in the treatment of other types of cancer. Also called gp96 heat shock protein-peptide complex vaccine, gp96 HSP-peptide complex, and vitespen.
Oncotype DX breast cancer assay: (ON-koh-tipe … brest KAN-ser A-say); A lab test that is used to help predict whether breast cancer will come back or spread to other parts of the body. The test looks at the activity level of 21 different genes in breast cancer tissue of people with early-stage (stage I, II, or IIIA) invasive breast cancer that is estrogen receptor (ER) positive, HER2 negative, and is either node-negative or has spread to 1 to 3 lymph nodes. If the test shows that there is a high risk that the cancer will spread or come back, treatment with chemotherapy may be needed to lower the risk. Also called 21-gene signature.
Oncotype DX ductal carcinoma in situ (DCIS) assay: (ON-koh-tipe … DUK-tul KAR-sih-NOH-muh in SY-too … A-say); A test that is being studied as a way to help predict whether ductal carcinoma in situ (DCIS) will come back or become invasive and spread to other tissues in the same breast. The test looks at the activity of 12 different genes in DCIS tissue, and it may be used to help plan treatment.
Oncovin: (ON-koh-vin); A drug that contains the active ingredient vincristine sulfate, which is used to treat many types of cancer. Oncovin brand has been taken off the market and is no longer available.
ondansetron hydrochloride: (on-DAN-seh-tron HY-droh-KLOR-ide); A drug used to prevent nausea and vomiting caused by chemotherapy and radiation therapy and nausea and vomiting after surgery. Ondansetron hydrochloride blocks the action of a chemical called serotonin, which binds to certain nerves and may trigger nausea and vomiting. Blocking serotonin may help lessen nausea and vomiting. Ondansetron hydrochloride is a type of antiemetic and a type of serotonin receptor antagonist. Also called Zofran.
Onivyde: (AH-nih-vide); A form of the anticancer drug irinotecan hydrochloride that is contained inside very tiny, fat-like particles and is used with other drugs to treat adults with pancreatic cancer that has spread to other parts of the body. It is used in patients whose cancer has not been treated with other anticancer therapy or has gotten worse after treatment with gemcitabine hydrochloride. It is also being studied in the treatment of other types of cancer. Onivyde may have fewer side effects and work better than other forms of irinotecan hydrochloride. Onivyde blocks a certain enzyme needed for cell division and DNA repair, and it may kill cancer cells. It is a type of topoisomerase inhibitor and a type of camptothecin analog. Also called irinotecan sucrosofate and PEP02.
Onrigin: (ON-rih-jin); A drug used to treat acute myelogenous leukemia (AML). It is also being studied in the treatment of several other types of cancer. It blocks cell growth by damaging the cell’s DNA and may kill cancer cells. It is a type of alkylating agent. Also called Cloretazine and laromustine.
onset of action: (... AK-shun); The length of time it takes for a medicine to start to work.
Ontruzant: (on-TROO-zant); A drug used alone or with other drugs to treat certain types of breast cancer, stomach cancer, and gastroesophageal junction cancer that are HER2 positive. It is also being studied in the treatment of other types of cancer. Ontruzant binds to a protein called HER2, which is found on some cancer cells. This may help the immune system kill cancer cells. Ontruzant is a type of monoclonal antibody and a type of HER2 receptor antagonist. Also called Herceptin, Hercessi, Herzuma, Kanjinti, Ogivri, trastuzumab, and Trazimera.
Onureg: (ON-yoo-reg); A drug that contains the active ingredient azacitidine and is used to treat adults with certain types of acute myeloid leukemia. It is used in patients whose cancer is in first complete remission after intensive induction chemotherapy and who were not able to finish intensive therapy that would cure their cancer. Onureg stops cells from making DNA and may kill cancer cells. It is a type of antimetabolite.
onychodystrophy: (ON-ih-koh-DIS-truh-fee); Abnormal changes in the shape, color, texture, and growth of the fingernails or toenails. Onychodystrophy is often caused by infection or injury to the nail. It may also be caused by certain conditions, including psoriasis, eczema, warts, cysts, and some tumors. Changes in nails can also be a sign of chronic heart, lung, liver, or kidney disease. Treatment with certain drugs, including chemotherapy drugs, can also cause changes to the nails. Also called nail dystrophy.
ONYX-015: A modified cold virus that selectively grows in and destroys certain types of cancer cells and leaves normal cells undamaged.
oocyte cryopreservation: (OH-oh-site KRY-oh-PREH-zer-VAY-shun); The process of freezing one or more unfertilized eggs (eggs that have not been combined with sperm) to save them for future use. The eggs are thawed and fertilized in the laboratory to make embryos that can be placed in a woman’s uterus. Oocyte cryopreservation is being studied as a type of fertility preservation. It may be useful for women with cancer who want to have children after having radiation therapy, chemotherapy, or certain types of surgery, which can cause infertility. Also called egg banking, egg cryopreservation, and egg freezing.
oophorectomy: (oh-oh-foh-REK-toh-mee); Surgery to remove one or both ovaries.
oophoropexy: (oh-oh-FOR-oh-PEK-see); A procedure used to help keep a woman fertile by preventing damage to the ovaries during radiation therapy. Before radiation therapy begins, one or both ovaries and fallopian tubes are separated from the uterus and attached to the wall of the abdomen away from where the radiation will be given. Oophoropexy may be useful for women who want to have children after having radiation therapy that can cause infertility. It is a type of fertility preservation. Also called ovarian transposition.
Opdivo: (op-DEE-voh); A drug that binds to the protein PD-1 to help immune cells kill cancer cells better and is used to treat many different types of cancer. These include cancers that express the protein PD-L1 or that have certain mutations (changes) in genes involved in DNA repair. Opdivo is used alone or with other drugs to treat certain types of classic Hodgkin lymphoma, colorectal cancer, esophageal cancer, gastroesophageal junction cancer, head and neck squamous cell carcinoma, hepatocellular carcinoma (a type of liver cancer), malignant pleural mesothelioma, melanoma, non-small cell lung cancer, renal cell carcinoma (a type of kidney cancer), stomach cancer, and urothelial carcinoma (a type of bladder or urinary tract cancer). It is also being studied in the treatment of other types of cancer. Opdivo may block PD-1 and help the immune system kill cancer cells. It is a type of monoclonal antibody and a type of immune checkpoint inhibitor. Also called nivolumab.
Opdivo Qvantig: (op-DEE-voh kyoo-VAN-tig); A combination of two drugs used alone or with other drugs to treat adults with certain types of colorectal cancer, esophageal cancer, gastric (stomach) cancer, gastroesophageal junction adenocarcinoma, hepatocellular carcinoma (a type of liver cancer), melanoma, non-small cell lung cancer, renal cell carcinoma (a type of kidney cancer), squamous cell carcinoma of the head and neck, and urothelial carcinoma (a type of cancer in the bladder or urinary tract). Nivolumab binds to a protein called PD-1, which is found on some normal cells and some types of cancer cells. Nivolumab may block PD-1 and help the immune system kill cancer cells. Hyaluronidase allows nivolumab to be given by injection under the skin. Opdivo Qvantig can be given in less time than nivolumab alone, which is given as an infusion. Also called nivolumab and hyaluronidase.
Opdualag: (op-DOO-uh-lag); A combination of nivolumab and relatlimab used to treat adults and children aged 12 years or older with melanoma that has spread or cannot be removed by surgery. It is also being studied in the treatment of other types of cancer. Opdualag binds to the proteins PD-1 and LAG-3, which are found on T cells (a type of immune cell). Blocking these proteins may help the immune system kill cancer cells. The combination of nivolumab and relatlimab may work better than either drug alone. Opdualag is a type of monoclonal antibody and a type of immune checkpoint inhibitor. Also called nivolumab and relatlimab.
open biopsy: (OH-pen BY-op-see); A procedure in which a cut is made through the skin to remove abnormal tissue so it can be checked under a microscope for signs of disease. The two types of open biopsy are incisional biopsy, in which part of a lump or a sample of tissue is removed, and excisional biopsy, in which an entire lump or suspicious area is removed. Also called surgical biopsy.
open colectomy: (... koh-LEK-toh-mee); An operation to remove all or part of the colon through a long incision made in the wall of the abdomen. When only part of the colon is removed, it is called a partial colectomy.
open label study: (OH-pen LAY-bel STUH-dee); A type of study in which both the health providers and the patients are aware of the drug or treatment being given. Also called nonblinded.
open radical prostatectomy: (… RA-dih-kul PROS-tuh-TEK-toh-mee); Surgery to remove the entire prostate and some of the tissue around it, including the seminal vesicles (a gland that helps make semen). Nearby lymph nodes may also be removed. During an open radical prostatectomy, an incision (cut) is made in the wall of the lower abdomen or in the perineum (the area between the scrotum and anus). An attempt is made to protect the nerves that control penile erection and the bladder from damage.
open resection: (… ree-SEK-shun); Surgery to remove part or all of an organ or a tumor and nearby lymph nodes. The incision is large enough to let the surgeon see into the body.
operable: (AH-peh-ruh-bul); Describes a condition that can be treated by surgery.
operation: (ah-per-AY-shun); A procedure to remove or repair a part of the body or to find out whether disease is present. Also called surgery.
ophthalmic: (of-THAL-mik); Having to do with the eye.
ophthalmic artery infusion: (of-THAL-mik AR-tuh-ree in-FYOO-zhun); A method of delivering anticancer drugs directly to a tumor in the eye. A catheter (a thin, flexible tube) is put into an artery that leads to the eye and the anticancer drug is given through the catheter. A small balloon may then be put into the artery to block it, which keeps the anticancer drug near the tumor. Ophthalmic artery infusion may be used to treat certain types of retinoblastoma.
ophthalmologist: (OF-thul-MAH-loh-jist); A doctor who has special training in diagnosing and treating eye problems, including injury and disease.
ophthalmoscope: (of-THAL-moh-skope); A lighted instrument used to examine the inside of the eye, including the retina and the optic nerve.
ophthalmoscopy: (OF-thul-MOS-koh-pee); An exam that uses a magnifying lens and a light to check the fundus of the eye (back of the inside of the eye, including the retina and optic nerve). The pupils may be dilated (enlarged) with medicated eye drops so the doctor can see through the pupil to the back of the eye. Ophthalmoscopy may be used to check for eye problems, such as glaucoma, macular degeneration, eye cancer, optic nerve problems, or eye injury. Also called fundoscopy and funduscopy.
opiate: (OH-pee-ut); A substance used to treat pain or cause sleep. Opiates are made from opium or have opium in them. Opiates bind to opioid receptors in the central nervous system. Examples of opiates are codeine, heroin, and morphine. An opiate is a type of analgesic agent.
opioid: (OH-pee-OYD); A class of drug used to reduce moderate to severe pain. Opioids can be made from the opium poppy plant or in the laboratory. They block pain signals by binding to opioid receptors on nerve cells in the brain, spinal cord, gastrointestinal tract, and other organs in the body. Some opioids may also be used to treat cough and diarrhea. Opioids used for pain relief are usually safe when taken for a short time and as prescribed by a health care provider, but they can be highly addictive and as a result have often been misused or abused.
opioid growth factor: (OH-pee-OYD grothe FAK-ter); A substance that relieves pain and is being studied in the treatment of some types of cancer. Opioid growth factors bind to cells in the body, including tumor cells, which have opioid growth factor receptors on the surface. This may help stop the growth of the tumor cells. It may also prevent the growth of blood vessels that tumors need to grow. An opioid growth factor is a type of biological response modifier and a type of antiangiogenesis agent. Also called OGF.
opium: (OH-pee-um); A highly addictive, natural substance that comes from the seed pods of the poppy plant, Papaver somniferum. Opium contains chemicals that affect the brain, causing pain relief and a feeling of euphoria. It is used to make medicines like morphine and codeine. Opium is dangerous when misused. High doses can slow breathing, cause unconsciousness, or lead to death.
OPMD: A group of conditions in which there are abnormal tissue changes in the mouth that may become cancer. These changes may include a lump, thickening, or abnormal patch of red and/or white tissue that forms on the lips, gums, tongue, inner lining of the cheeks, or other areas in the mouth. There are many different types of OPMDs, but the most common types are leukoplakia and erythroplakia. OPMDs may occur in people who have certain rare hereditary conditions, including dyskeratosis congenita, epidermolysis bullosa, xeroderma pigmentosum, and Plummer-Vinson syndrome. Having an OPMD increases a person’s risk of developing oral cancer. Also called oral potentially malignant disorder.
OPPA: An abbreviation for a chemotherapy combination that is often used with radiation therapy to treat a certain type of childhood Hodgkin lymphoma in females. It includes the drugs vincristine sulfate (Oncovin), prednisone, procarbazine hydrochloride, and doxorubicin hydrochloride (Adriamycin). Also called OPPA regimen.
OPPA regimen: (... REH-jih-men); An abbreviation for a chemotherapy combination that is often used with radiation therapy to treat a certain type of childhood Hodgkin lymphoma in females. It includes the drugs vincristine sulfate (Oncovin), prednisone, procarbazine hydrochloride, and doxorubicin hydrochloride (Adriamycin). Also called OPPA.
opportunistic infection: (AH-per-too-NIS-tik in-FEK-shun); An infection caused by an organism that does not normally cause disease. Opportunistic infections occur in people with weakened immune systems.
oprelvekin: (oh-PREL-veh-KIN); A drug used to increase the number of blood cells, especially platelets, in some cancer patients receiving chemotherapy. Oprelvekin 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, recombinant human interleukin-11, and rhIL-11.
OPT-80: A substance being studied in the treatment of diarrhea caused by infection with Clostridium difficile (a type of bacteria that can grow without oxygen) in cancer patients. OPT-80 is a type of antibiotic. Also called PAR-101 and tiacumicin B.
optic chiasm: (OP-tik ky-A-zum); The place in the brain where some of the optic nerve fibers coming from one eye cross optic nerve fibers from the other eye. Also called optic chiasma.
optic chiasma: (OP-tik ky-AZ-muh); The place in the brain where some of the optic nerve fibers coming from one eye cross optic nerve fibers from the other eye. Also called optic chiasm.
optic nerve: (OP-tik nerv); The nerve that carries messages from the retina to the brain.
optic neuritis: (OP-tik noo-RY-tis); Inflammation of the optic nerve (the nerve that carries messages from the back of the eye to the brain). It may be caused by infection, drugs, toxins, and diseases of the immune system, such as multiple sclerosis. Symptoms include sudden changes in vision in one eye, including loss of vision and pain with eye movement. The symptoms often disappear within a few weeks.
optic pathway glioma: (OP-tik ... glee-OH-muh); A rare, slow-growing tumor that usually forms in the optic nerve, optic chiasm, or optic tract. These are parts of the nervous system that carry messages from the eye to the brain. Also called visual pathway glioma.
optic tract: (OP-tik trakt); The nerves that travel from the optic chiasm (place in the brain where some of the optic nerve fibers cross) into certain parts of the brain involved in vision.
optical coherence tomography: (OP-tih-kul koh-HEER-ents toh-MAH-gruh-fee); A procedure that uses infrared light waves to give three-dimensional (3-D) pictures of structures inside tissues and organs. The pictures are made by a computer linked to the light source. Also called OCT.
optical spectroscopy: (OP-tih-kul spek-TROS-koh-pee); In medicine, a technique that uses low power light, fiberoptic instruments, and detectors to examine tissue. It is being studied as a way to identify differences between normal cells and cells that may become cancer, and as a way to identify cancer cells that remain in the edges of tumor tissue removed from a patient.
optimism: (OP-tih-MIH-zum); The tendency to believe that there is good in everything and to have positive thoughts about most things that happen.
oral: (OR-ul); By or having to do with the mouth.
oral and maxillofacial surgeon: (OR-ul ... MAK-sih-loh-FAY-shul SER-jun); A dentist who has special training in surgery of the mouth, face, and jaw.
oral cancer: (OR-ul KAN-ser); Cancer that forms in tissues of the oral cavity (the mouth) or the oropharynx (the part of the throat at the back of the mouth).
oral cavity: (OR-ul KA-vih-tee); Refers to the mouth. It includes the lips, the lining inside the cheeks and lips, the front two thirds of the tongue, the upper and lower gums, the floor of the mouth under the tongue, the bony roof of the mouth, and the small area behind the wisdom teeth.
oral cavity cancer: (OR-ul KA-vih-tee KAN-ser); Cancer that forms in tissues of the oral cavity (the mouth). The tissues of the oral cavity include the lips, the lining inside the cheeks and lips, the front two thirds of the tongue, the upper and lower gums, the floor of the mouth under the tongue, the bony roof of the mouth, and the small area behind the wisdom teeth.
oral chemotherapy: (OR-ul KEE-moh-THAYR-uh-pee); Treatment with drugs given by mouth to kill cancer cells or stop them from dividing.
oral contraceptive pill: (OR-ul KON-truh-SEP-tiv ...); A pill used to prevent pregnancy. It contains hormones that block the release of eggs from the ovaries. Most oral contraceptives include estrogen and progestin. Also called birth control pill.
oral dysplasia: (OR-ul dis-PLAY-zhuh); The presence of abnormal cells in the tissues of the mouth. These tissues include the lips, the lining of the inside of the cheeks, the gums, the front two thirds of the tongue, the bottom of the mouth under the tongue, the bony part of the roof of the mouth, and the small area behind the wisdom teeth. Oral dysplasia may be found in patches of tissue that look red, white, or a mixture of both colors but can only be diagnosed by looking at the cells under a microscope. It is most commonly caused by tobacco or alcohol use. It may also be caused by infection with certain types of human papillomavirus (HPV). Oral dysplasia is not cancer but may become cancer and spread to nearby normal tissue. It can be mild, moderate, or severe, depending on how abnormal the cells look under a microscope and how much of the tissues in the mouth are affected. Also called OED and oral epithelial dysplasia.
oral epithelial dysplasia: (OR-ul eh-pih-THEE-lee-ul dis-PLAY-zhuh); The presence of abnormal cells in the tissues of the mouth. These tissues include the lips, the lining of the inside of the cheeks, the gums, the front two thirds of the tongue, the bottom of the mouth under the tongue, the bony part of the roof of the mouth, and the small area behind the wisdom teeth. Oral epithelial dysplasia may be found in patches of tissue that look red, white, or a mixture of both colors but can only be diagnosed by looking at the cells under a microscope. It is most commonly caused by tobacco or alcohol use. It may also be caused by infection with certain types of human papillomavirus (HPV). Oral epithelial dysplasia is not cancer but may become cancer and spread to nearby normal tissue. It can be mild, moderate, or severe, depending on how abnormal the cells look under a microscope and how much of the tissues in the mouth are affected. Also called OED and oral dysplasia.
oral papilloma: (OR-ul PA-pih-LOH-muh); A benign (not cancer), wart-like growth that occurs on the lips or in the mouth, including the tongue, gums, tonsils, and back of the throat. Oral papillomas often appear as pink or white bumps that may be different sizes. They are usually painless and do not cause symptoms. Oral papillomas may be caused by chronic infection with certain types of human papillomavirus (HPV). They may also be found in people with a rare, inherited condition called Cowden syndrome. Oral papillomas most often occur in adults.
oral potentially malignant disorder: (OR-ul poh-TEN-shuh-lee muh-LIG-nunt dis-OR-der); A group of conditions in which there are abnormal tissue changes in the mouth that may become cancer. These changes may include a lump, thickening, or abnormal patch of red and/or white tissue that forms on the lips, gums, tongue, inner lining of the cheeks, or other areas in the mouth. There are many different types of oral potentially malignant disorders, but the most common types are leukoplakia and erythroplakia. Oral potentially malignant disorders may occur in people who have certain rare hereditary conditions, including dyskeratosis congenita, epidermolysis bullosa, xeroderma pigmentosum, and Plummer-Vinson syndrome. Having an oral potentially malignant disorder increases a person’s risk of developing oral cancer. Also called OPMD.
oral surgeon: (OR-ul SER-jun); A dentist with special training in surgery of the mouth and jaw.
orantinib: (oh-RAN-tih-nib); A substance being studied in the treatment of cancer. Orantinib blocks proteins involved in the growth and spread of cancer cells. It may also prevent the growth of new blood vessels that tumors need to grow. It is a type of tyrosine kinase inhibitor and a type of antiangiogenesis agent. Also called SU006668 and SU6668.
orbit: (OR-bit); The space within the skull that contains the eye, including its nerves and muscles. The orbit also includes the eyelids and the glands that make tears. It is made up of seven bones that surround and protect the eye. Also called eye socket.
orchidectomy: (or-kih-DEK-toh-mee); Surgery to remove one or both testicles. Also called orchiectomy.
orchiectomy: (or-kee-EK-toh-mee); Surgery to remove one or both testicles. Also called orchidectomy.
oregovomab: (oh-reh-GOH-voh-mab); A monoclonal antibody that is being studied in the treatment of ovarian cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. Oregovomab binds to the CA-125 antigen, which is found on most ovarian cancer cells. Also called OvaRex.
organ: (OR-gun); In medicine, a part of the body that is made up of cells and tissues that perform a specific function. Examples of organs include the heart, lungs, stomach, liver, kidney, skin, spleen, uterus, and ovary.
organelle: (OR-guh-NEL); A small structure in a cell that is surrounded by a membrane and has a specific function. Examples of organelles are the nucleus (a structure that contains the cell’s chromosomes and is where RNA is made), mitochondria (structures that make energy for the cell), and lysosomes (sac-like containers filled with enzymes that digest and help recycle molecules in the cell).
organic food: (or-GA-nik …); Food produced without the use of man-made fertilizer, drugs that increase growth, or drugs that kill insects, bacteria, or other living things. In the United States, the Department of Agriculture sets standards for growing, harvesting, processing, and labeling organic foods.
organism: (OR-guh-NIH-zum); A living thing, such as an animal, a plant, a bacterium, or a fungus.
organism strain: (OR-guh-NIH-zum …); A group of organisms that belong to the same species but share certain genetic characteristics not found in other members of the species. Microorganisms, such as viruses, bacteria, and fungi, have many strains within a single species. Different strains of an organism may have different biological characteristics, such as the ability to cause more severe disease.
organoid: (OR-guh-noyd); A 3-dimensional, mini-organ-like structure made by growing a person's tumor cells or stem cells (cells from which other types of cells develop) in the laboratory. Organoids contain many types of cells and closely mimic the structure, organization, and some of the functions of human tissues and organs. Organoids made from a person's tumor cells have histologic, genomic, molecular, and other features that are similar to those found in the original tumor. Organoids are used in the laboratory to study how normal tissues or diseases, such as cancer, form and to test new drugs and other types of treatment before they are given to people.
orgasm: (OR-ga-zum); The final part of the sex act, which involves contraction of sexual organs and a sudden release of endorphins, leading to a feeling of pleasure. In males, orgasm usually occurs with release of semen.
Orgovyx: (or-GOH-vix); A drug used to treat adults with advanced prostate cancer. Orgovyx binds to gonadotropin-releasing hormone (GnRH) receptors in the pituitary gland, which blocks the pituitary gland from making the hormones follicle-stimulating hormone (FSH) and luteinizing hormone (LH). This causes the testicles to stop making testosterone. Orgovyx may stop the growth of cancer cells that need testosterone to grow. It is a type of GnRH antagonist. Also called relugolix.
Oriental medicine: (OR-ee-EN-tul MEH-dih-sin); A medical system that has been used for thousands of years to prevent, diagnose, and treat disease. It is based on the belief that qi (the body's vital energy) flows along meridians (channels) in the body and keeps a person’s spiritual, emotional, mental, and physical health in balance. Oriental medicine aims to restore the body’s balance and harmony between the natural opposing forces of yin and yang, which can block qi and cause disease. Oriental medicine includes acupuncture, diet, herbal therapy, meditation, physical exercise, and massage. Also called TCM and Traditional Chinese Medicine.
oropharyngeal cancer: (OR-oh-fuh-RIN-jee-ul KAN-ser); Cancer that forms in tissues of the oropharynx (the middle part of the throat, behind the mouth). The oropharynx includes the soft palate (the back muscular part of the roof of the mouth), the side and back walls of the throat, the tonsils, and the back one-third of the tongue. Most oropharyngeal cancers are squamous cell carcinomas (cancer that begins in the thin, flat cells lining the inside of the oropharynx).
oropharynx: (OR-oh-FAYR-inx); The middle part of the throat, behind the mouth. The oropharynx includes the soft palate (the back muscular part of the roof of the mouth), the side and back walls of the throat, the tonsils, and the back one-third of the tongue.
orphan drug: (OR-fun …); A drug used to treat, prevent, or diagnose an orphan disease. An orphan disease is a rare disease or condition that affects fewer than 200,000 people in the United States. Orphan diseases are often serious or life threatening. In 1983, the U.S. government passed a law, called the Orphan Drug Act, to give drug companies certain financial benefits for developing orphan drugs that are safe and effective.
orphan drug designation: (OR-fun … DEH-zig-NAY-shun); A status given to certain drugs called orphan drugs, which show promise in the treatment, prevention, or diagnosis of orphan diseases. An orphan disease is a rare disease or condition that affects fewer than 200,000 people in the United States. Orphan diseases are often serious or life threatening. In 1983, the U.S. government passed a law, called the Orphan Drug Act, to give drug companies certain financial benefits for developing orphan drugs. This law is meant to help bring more drugs to patients with rare diseases.
ORR: The percentage of people in a study or treatment group who have a partial response or complete response to the treatment within a certain period of time. A partial response is a decrease in the size of a tumor or in the amount of cancer in the body, and a complete response is the disappearance of all signs of cancer in the body. In a clinical trial, measuring the ORR is one way to see how well a new treatment works. Also called objective response rate.
Orserdu: (or-SER-doo); A drug used to treat postmenopausal women and adult men with estrogen receptor-positive, HER2-negative breast cancer that has a mutation (change) in the ESR1 gene and is advanced or has spread to other parts of the body. It is used in patients whose disease got worse after treatment with at least one type of hormone therapy. Orserdu binds to proteins called estrogen receptors, which are found on some breast cancer cells. These proteins may cause cancer cells to grow. Orserdu blocks these proteins and may keep cancer cells from growing. It is a type of estrogen receptor antagonist. Also called elacestrant dihydrochloride.
orthodontist: (OR-thuh-DON-tist); A dentist who has special training in preventing, diagnosing, and treating certain problems of the teeth and jaws, such as crooked or crowded teeth and bite problems. An orthodontist uses braces, aligners, retainers, headgear, and other devices to help straighten teeth, hold teeth in place, and improve bite. This can improve overall dental health, chewing, speech, and facial appearance.
orthodox medicine: (OR-thuh-DOX MEH-dih-sin); A system in which medical doctors and other health care professionals (such as nurses, pharmacists, and therapists) treat symptoms and diseases using drugs, radiation, or surgery. Also called allopathic medicine, biomedicine, conventional medicine, mainstream medicine, and Western medicine.
orthopedic surgeon: (OR-thuh-PEE-dik SER-jun); A surgeon who has special training in diagnosing and treating injuries and diseases of the musculoskeletal system. This includes the bones, joints, tendons, ligaments, and muscles.
orthotopic: (OR-thoh-TAH-pik); In medicine, refers to something that occurs in the normal or usual place in the body. It is often used to describe tissue or an organ that is transplanted into its normal place in the body.
OS: The length of time from either the date of diagnosis or the start of treatment for a disease, such as cancer, that patients diagnosed with the disease are still alive. In a clinical trial, measuring the OS is one way to see how well a new treatment works. Also called overall survival.
oseltamivir phosphate: (oh-sel-TA-mih-veer FOS-fayt); 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 Tamiflu.
OSI-774: A drug used alone to treat certain types of non-small cell lung cancer and with gemcitabine hydrochloride to treat certain types of pancreatic cancer. It is also being studied in the treatment of other types of cancer. OSI-774 blocks a protein called EGFR, which may help keep cancer cells from growing. It is a type of tyrosine kinase inhibitor. Also called CP-358,774, erlotinib hydrochloride, and Tarceva.
OSI-7904L: A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called thymidylate synthase inhibitors.
OSI-906: A substance being studied in the treatment of cancer. It blocks a protein called IGF-1R, which is found at high levels in some types of tumors. IGF-1R is needed for cell growth and blocking it may cause tumor cells to die. OSI-906 is a type of IGF-1R inhibitor. Also called IGF-1R inhibitor OSI-906.
osimertinib mesylate: (OH-sih-MER-tih-nib MEH-zih-layt); A drug used alone or with other drugs to treat adults with certain types of non-small cell lung cancer that have an abnormal EGFR gene. It is also being studied in the treatment of other types of cancer. Osimertinib mesylate blocks certain proteins made by the mutated EGFR gene, which may help keep cancer cells from growing and may kill them. It is a type of tyrosine kinase inhibitor. Also called Tagrisso.
osmolality: (OZ-moh-LA-lih-tee); The concentration of particles dissolved in a fluid. The osmolality of serum can help diagnose several medical conditions such as dehydration, diabetes, and shock.
osmotic: (oz-MAH-tik); Having to do with osmosis (the passage of a liquid through a membrane from a less concentrated solution to a more concentrated one). This causes the more concentrated solution to become diluted, and makes the concentrations in both solutions more equal. Osmotic also refers to a type of laxative that increases the amount of water in the large intestine, which softens the stool to help it pass more easily.
osseous tissue: (AH-see-us TIH-shoo); Tissue that gives strength and structure to bones. Bone is made up of compact tissue (the hard, outer layer) and cancellous tissue (the spongy, inner layer that contains red marrow). Osseous tissue is maintained by bone-forming cells called osteoblasts and cells that break down bone called osteoclasts. Bones also contain blood vessels, nerves, proteins, vitamins, and minerals. Also called bone tissue.
osteitis deformans: (OS-tee-I-tis dih-FOR-manz); A chronic condition in which both the breakdown and regrowth of bone are increased. Osteitis deformans occurs most frequently in the pelvic and leg bones, skull, and lower spine. It is most common in older individuals, and may lead to bone pain, deformities, and fractures. Also called Paget disease of bone.
osteochondroma: (OS-tee-oh-kon-DROH-muh); A benign (not cancer) tumor that has both bone and cartilage in it. This type of tumor usually occurs at the ends of the long bones of the arms and legs or in the pelvis or shoulder. It may cause abnormal growth of the arms, hands, and legs; problems moving the joints; and pain, numbness, and tingling. There may be one or more tumors, and having multiple tumors runs in families. Osteochondromas may also occur at some point in time after cancer treatment, such as stem cell transplant.
osteogenic sarcoma: (OS-tee-oh-JEH-nik sar-KOH-muh); A cancer of the bone that usually affects the large bones of the arm or leg. It occurs most commonly in young people and affects more males than females. Also called osteosarcoma.
osteolytic: (OS-tee-oh-LIH-tik); Causing the breakdown of bone.
osteomalacia: (OS-tee-oh-muh-LAY-shuh); A condition in adults in which bones become soft and deformed because they don’t have enough calcium and phosphorus. It is usually caused by not having enough vitamin D in the diet, not getting enough sunlight, or a problem with the way the body uses vitamin D. Symptoms include bone pain and muscle weakness. When the condition occurs in children, it is called rickets. Also called adult rickets.
osteomyelitis: (OS-tee-oh-MY-eh-LY-tis); Inflammation of the bone caused by an infection, which may spread to the bone marrow and tissues near the bone. Osteomyelitis can cause severe pain in the infected bone. If it is not treated, it can kill bone tissue.
osteonecrosis: (OS-tee-oh-neh-KROH-sis); A condition in which there is a loss of blood flow to bone tissue, which causes the bone to die. It is most common in the hips, knees, shoulders, and ankles. It may be caused by long-term use of steroid medicines, alcohol abuse, joint injuries, and certain diseases, such as cancer and arthritis. It may also occur at some point in time after cancer treatment that included methotrexate, bisphosphonates, or corticosteroids. Also called aseptic necrosis, avascular necrosis, and ischemic necrosis.
osteopenia: (OS-tee-oh-PEE-nee-uh); A condition in which there is a lower-than-normal bone mass or bone mineral density (the amount of bone mineral contained in a certain amount of bone). Osteopenia is a less severe form of bone loss than osteoporosis.
osteoporosis: (OS-tee-oh-puh-ROH-sis); A condition in which there is a decrease in the amount and thickness of bone tissue. This causes the bones to become weak and break more easily. Osteoporosis may be caused by older age, hormone changes, taking certain medicines, and not eating enough foods with calcium and vitamin D. It may also be caused by certain types of cancer and cancer treatment. It is most common in white and Asian women.
osteosarcoma: (OS-tee-oh-sar-KOH-muh); A cancer of the bone that usually affects the large bones of the arm or leg. It occurs most commonly in young people and affects more males than females. Also called osteogenic sarcoma.
ostomy: (OS-toh-mee); An operation to create an opening (a stoma) from an area inside the body to the outside. Colostomy and urostomy are types of ostomies.
OTC: Refers to a medicine that can be bought without a prescription (doctor's order). Examples include analgesics (pain relievers), such as aspirin and acetaminophen. Also called nonprescription and over-the-counter.
otolaryngologist: (OH-toh-LAYR-in-GAH-loh-jist); A doctor who has special training in diagnosing and treating diseases of the ear, nose, and throat. Also called ENT doctor.
ounce: (ownts); A measure of weight (one-sixteenth pound) and volume (one-eighth cup).
out-of-pocket cost: (…PAH-kit …); In medicine, the amount of money a patient pays for medical expenses that are not covered by a health insurance plan. Out-of-pocket costs include deductibles, coinsurance, copayments, and costs for noncovered health care services.
outcome: (OWT-kum); A specific result or effect that can be measured. Examples of outcomes include decreased pain, reduced tumor size, and improvement of disease.
outpatient: (OWT-pay-shunt); A patient who visits a health care facility for diagnosis or treatment without spending the night. Sometimes called a day patient.
OvaRex: (OH-vuh-REX); A monoclonal antibody that is being studied in the treatment of ovarian cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. OvaRex binds to the CA-125 antigen, which is found on most ovarian cancer cells. Also called oregovomab.
ovarian: (oh-VAYR-ee-un); Having to do with the ovaries, the female reproductive glands in which the ova (eggs) are formed. The ovaries are located in the pelvis, one on each side of the uterus.
ovarian ablation: (oh-VAYR-ee-un a-BLAY-shun); Treatment that stops or lowers the amount of estrogen made by the ovaries. Types of ovarian ablation include surgery to remove both ovaries, radiation therapy, and the use of certain drugs. Ovarian ablation may be used to prevent and treat breast cancer. Also called ovarian suppression.
ovarian borderline malignant tumor: (oh-VAYR-ee-un BOR-der-line muh-LIG-nunt TOO-mer); A condition in which abnormal cells that may become cancer form in the tissue that covers the ovary (one of a pair of female reproductive glands in which eggs are made). Ovarian borderline malignant tumors rarely spread outside of the ovary. Also called ovarian borderline tumor and ovarian low malignant potential tumor.
ovarian borderline tumor: (oh-VAYR-ee-un BOR-der-line TOO-mer); A condition in which abnormal cells that may become cancer form in the tissue that covers the ovary (one of a pair of female reproductive glands in which eggs are made). Ovarian borderline tumors rarely spread outside of the ovary. Also called ovarian borderline malignant tumor and ovarian low malignant potential tumor.
ovarian cancer: (oh-VAYR-ee-un KAN-ser); Cancer that forms in tissues of the ovary (one of a pair of female reproductive glands in which the ova, or eggs, are formed). Most ovarian cancers are either ovarian epithelial cancers (cancer that begins in the cells on the surface of the ovary) or malignant germ cell tumors (cancer that begins in egg cells). Fallopian tube cancer and primary peritoneal cancer are similar to ovarian epithelial cancer and are staged and treated the same way.
ovarian epithelial cancer: (oh-VAYR-ee-un eh-pih-THEE-lee-ul KAN-ser); Cancer that forms in the tissue covering the ovary (one of a pair of female reproductive glands in which eggs are made). Most ovarian cancers are ovarian epithelial cancers. Fallopian tube cancer and primary peritoneal cancer are similar to ovarian epithelial cancer and are staged and treated the same way. Also called epithelial ovarian cancer.
ovarian failure: (oh-VAYR-ee-un FAYL-yer); A condition in which the ovaries stop working and menstrual periods stop before age 40. This can cause fertility problems and symptoms of menopause. There are two types of ovarian failure, primary and secondary. Primary ovarian failure means that the ovaries do not function normally. This may be because they have been removed by surgery, or it may be caused by some cancer treatments and certain diseases or genetic conditions. In secondary ovarian failure, the ovaries are normal but there is a problem getting hormone signals to them from the brain. This is usually caused by diseases of the pituitary gland or hypothalamus. Some women with ovarian failure sometimes have menstrual periods and may be able to have children. Also called early menopause, ovarian insufficiency, and premature menopause.
ovarian follicle: (oh-VAYR-ee-un FAH-lih-kul); A small, fluid-filled sac in the ovary that contains one immature egg. There are thousands of follicles in the ovaries. When an egg matures during a woman’s menstrual cycle, the follicle breaks open and releases the egg from the ovary for possible fertilization (the process by which an egg combines with sperm to form an embryo). Ovarian follicles may sometimes be checked to help diagnose and treat infertility.
ovarian germ cell tumor: (oh-VAYR-ee-un jerm sel TOO-mer); An abnormal mass of tissue that forms in germ (egg) cells in the ovary (female reproductive gland in which the eggs are formed). These tumors usually occur in teenage girls or young women, usually affect just one ovary, and can be benign (not cancer) or malignant (cancer). The most common ovarian germ cell tumor is called dysgerminoma.
ovarian insufficiency: (oh-VAYR-ee-un IN-suh-FIH-shen-see); A condition in which the ovaries stop working and menstrual periods stop before age 40. This can cause fertility problems and symptoms of menopause. There are two types of ovarian insufficiency, primary and secondary. Primary ovarian insufficiency means that the ovaries do not function normally. This may be because they have been removed by surgery, or it may be caused by some cancer treatments and certain diseases or genetic conditions. In secondary ovarian insufficiency, the ovaries are normal but there is a problem getting hormone signals to them from the brain. This is usually caused by diseases of the pituitary gland or hypothalamus. Some women with ovarian insufficiency sometimes have menstrual periods and may be able to have children. Also called early menopause, ovarian failure, and premature menopause.
ovarian low malignant potential tumor: (oh-VAYR-ee-un...muh-LIG-nunt poh-TEN-shul TOO-mer); A condition in which abnormal cells that may become cancer form in the tissue that covers the ovary (one of a pair of female reproductive glands in which eggs are made). Ovarian low malignant potential tumors rarely spread outside of the ovary. Also called ovarian borderline malignant tumor and ovarian borderline tumor.
ovarian reserve: (oh-VAYR-ee-un reh-SERV); The total number of healthy, immature eggs in the ovaries. The number of healthy eggs decreases as a woman ages, which can lower fertility (the ability to have children). Damage to the ovaries can also decrease ovarian reserve and fertility. This may be caused by smoking, certain anticancer treatments (such as chemotherapy or radiation therapy), surgery to the ovaries or other organs in the pelvis, and certain diseases or genetic conditions. Ovarian reserve is often checked in women who want to have children and are having problems getting pregnant.
ovarian shielding: (oh-VAYR-ee-un SHEEL-ding); A procedure done during radiation therapy in which a protective cover is placed on the outside of the body, over the area of the ovaries and other parts of the female reproductive system (ovaries, fallopian tubes, uterus, cervix, and vagina). This may prevent damage from radiation therapy. Ovarian shielding is a type of fertility preservation.
ovarian suppression: (oh-VAYR-ee-un suh-PREH-shun); Treatment that stops or lowers the amount of estrogen made by the ovaries. Types of ovarian suppression include surgery to remove both ovaries, radiation therapy, and the use of certain drugs. Ovarian suppression may be used to prevent and treat breast cancer. Also called ovarian ablation.
ovarian tissue banking: (oh-VAYR-ee-un TIH-shoo BANK-ing); The process of freezing ovarian tissue to save for future infertility treatment. Part or all of an ovary is removed, and the tissue that contains the eggs is cut into thin slices and frozen. The tissue may later be thawed and placed back into the woman’s body, usually on the remaining ovary. Ovarian tissue banking is a type of fertility preservation. It may be useful for women who want to have children after having treatment that may cause infertility, such as certain cancer treatments. Also called ovarian tissue cryopreservation and ovarian tissue freezing.
ovarian tissue cryopreservation: (oh-VAYR-ee-un TIH-shoo KRY-oh-PREH-zer-VAY-shun); The process of freezing ovarian tissue to save for future infertility treatment. Part or all of an ovary is removed, and the tissue that contains the eggs is cut into thin slices and frozen. The tissue may later be thawed and placed back into the woman’s body, usually on the remaining ovary. Ovarian tissue cryopreservation is a type of fertility preservation. It may be useful for women who want to have children after having treatment that may cause infertility, such as certain cancer treatments. Also called ovarian tissue banking and ovarian tissue freezing.
ovarian tissue freezing: (oh-VAYR-ee-un TIH-shoo FREE-zing); The process of freezing ovarian tissue to save for future infertility treatment. Part or all of an ovary is removed, and the tissue that contains the eggs is cut into thin slices and frozen. The tissue may later be thawed and placed back into the woman’s body, usually on the remaining ovary. Ovarian tissue freezing is a type of fertility preservation. It may be useful for women who want to have children after having treatment that may cause infertility, such as certain cancer treatments. Also called ovarian tissue banking and ovarian tissue cryopreservation.
ovarian transposition: (oh-VAYR-ee-un tranz-poh-ZIH-shun); A procedure used to help keep a woman fertile by preventing damage to the ovaries during radiation therapy. Before radiation therapy begins, one or both ovaries and fallopian tubes are separated from the uterus and attached to the wall of the abdomen away from where the radiation will be given. Ovarian transposition may be useful for women who want to have children after having radiation therapy that can cause infertility. It is a type of fertility preservation. Also called oophoropexy.
ovary: (OH-vuh-ree); One of a pair of female glands in which the eggs form and the female hormones estrogen and progesterone are made. These hormones play an important role in female traits, such as breast development, body shape, and body hair. They are also involved in the menstrual cycle, fertility, and pregnancy. There is one ovary on each side of the uterus.
over-the-counter: (OH-ver-the-KOWN-ter); Refers to a medicine that can be bought without a prescription (doctor's order). Examples include analgesics (pain relievers), such as aspirin and acetaminophen. Also called nonprescription and OTC.
overactive thyroid: (... THY-royd); A condition that occurs when the thyroid gland makes more thyroid hormones than the body needs. Thyroid hormones control the way the body uses energy and affect the body’s metabolism. Overactive thyroid may be caused by an autoimmune disorder called Graves’ disease, benign lumps in the thyroid gland, and inflammation of the thyroid gland. It may also be caused by consuming too much iodine in the diet or by taking too much thyroid hormone medicine. Signs and symptoms include weight loss, fatigue, rapid or irregular heartbeat, sweating, diarrhea, nervousness, mood swings, shaky hands, trouble sleeping, trouble tolerating heat, muscle weakness, and a goiter (an enlarged thyroid gland that may cause the bottom of the neck to look swollen). Overactive thyroid can usually be controlled with treatment. Also called hyperthyroidism.
overall survival: (oh-ver-AWL ser-VY-vul); The length of time from either the date of diagnosis or the start of treatment for a disease, such as cancer, that patients diagnosed with the disease are still alive. In a clinical trial, measuring the overall survival is one way to see how well a new treatment works. Also called OS.
overall survival rate: (oh-ver-AWL ser-VY-vul rayt); The percentage of people in a study or treatment group who are still alive for a certain period of time after they were diagnosed with or started treatment for a disease, such as cancer. The overall survival rate is often stated as a five-year survival rate, which is the percentage of people in a study or treatment group who are alive five years after their diagnosis or the start of treatment. Also called survival rate.
overdiagnosis: (OH-ver-DY-ug-NOH-sis); Finding cases of cancer with a screening test (such as a mammogram or PSA test) that will never cause any symptoms. These cancers may just stop growing or go away on their own. Some of the harms caused by overdiagnosis are anxiety and having treatments that are not needed.
overdose: (OH-ver-dose); An amount of drug that is more than what should be taken at one time.
overexpress: (OH-ver-ek-SPRES); In biology, to make too many copies of a protein or other substance. Overexpression of certain proteins or other substances may play a role in cancer development.
overgrowth syndrome: (OH-ver-grothe SIN-drome); A group of genetic disorders in which there is an abnormal increase in the size of the body or a body part that is often noted at birth. Examples of overgrowth syndromes include neurofibromatosis, Sotos syndrome, Beckwith-Wiedemann syndrome, Simpson-Golabi-Behmel syndrome, Weaver syndrome, Proteus syndrome, Sturge-Weber syndrome, and fragile X syndrome. Many of these syndromes increase the risk of cancer.
overtreatment: (OH-ver-TREET-ment); Unnecessary treatment for a condition that is not life-threatening or would never cause any symptoms. Overtreatment may lead to problems and harmful side effects. Overtreatment can be a result of overdiagnosis, which occurs when a cancer screening test finds a lesion that would have gone away on its own or not caused problems.
overweight: (OH-ver-WAYT); A common condition marked by weighing more than what is thought to be healthy for one’s height. Excess body weight can come from extra fat, muscle, and/or fluid in the tissues. Overweight is generally defined as having a body mass index (BMI) between 25 and 29. Factors that may increase a person’s risk of having overweight include a poor diet, stress, not getting enough sleep or exercise, and taking certain medicines. A person’s genetics and some health conditions, such as metabolic syndrome and polycystic ovarian syndrome, can also lead to having overweight. Having overweight can increase the risk of many health problems, including diabetes, high blood pressure, heart disease, stroke, sleep apnea, arthritis, and certain types of cancer.
ovulation: (ov-yoo-LAY-shun); The release of an egg from an ovary during the menstrual cycle.
OX-40: A protein being studied in the treatment of cancer. Substances that attach to OX-40 on the surface of T cells (a type of white blood cell) may help the T cells grow and kill more cancer cells. OX-40 is a type of tumor necrosis factor (TNF) receptor. Also called CD134.
oxaliplatin: (ok-SA-lih-pla-tin); A drug used with other drugs to treat stage III colon cancer that was removed by surgery and colorectal cancer that is advanced. It is also being studied in the treatment of other types of cancer. Oxaliplatin damages the cell’s DNA and may kill cancer cells. It is a type of platinum compound. Also called Eloxatin.
oxandrolone: (ok-SAN-droh-lone); A drug used to help patients gain weight after injury, chronic infection, or severe illness. It belongs to the family of drugs called anabolic steroids.
oxidation: (OK-sih-DAY-shun); A chemical reaction that takes place when a substance comes into contact with oxygen or another oxidizing substance. Examples of oxidation are rust and the brown color on a cut apple.
oxidation-reduction: (OK-sih-DAY-shun-ree-DUK-shun); A chemical reaction that takes place between an oxidizing substance and a reducing substance. The oxidizing substance loses electrons in the reaction, and the reducing substance gains electrons. For example, rust forms when there is an oxidation-reduction reaction between oxygen contained in water or moist air (an oxidizing substance) and iron (a reducing substance). Oxidation-reduction reactions also occur when glucose (a type of sugar) and fat are broken down in the body to make energy. Also called redox.
oxidative metabolism: (OK-sih-DAY-tiv meh-TA-buh-lih-zum); A chemical process in which oxygen is used to make energy from carbohydrates (sugars). Also called aerobic metabolism, aerobic respiration, and cell respiration.
oxidative stress: (OK-sih-DAY-tiv ...); A condition that may occur when there are too many unstable molecules called free radicals in the body and not enough antioxidants to get rid of them. This can lead to cell and tissue damage. There are many factors that may lead to oxidative stress, including obesity, poor diet, smoking, drinking alcohol, taking certain medicines, and exposure to environmental factors such as radiation, toxins, air pollution, pesticides, and sunlight. Long-term oxidative stress may play a role in aging and the development of chronic inflammation, cancer, and other diseases.
oxide: (OK-side); A type of chemical substance that is a combination of oxygen and another substance. Oxides are found in essential oils.
oxidize: (OK-sih-dize); To cause oxidation (a chemical reaction that takes place when a substance comes into contact with oxygen or another oxidizing substance).
oxycodone hydrochloride: (OK-see-KOH-done HY-droh-KLOR-ide); A drug used to relieve moderate to severe pain. Oxycodone hydrochloride is made in a lab by modifying thebaine, a natural substance found in the opium poppy plant. It works by binding to mu opioid receptors in the central nervous system, which blocks pain signals and changes how the body responds to pain. Oxycodone hydrochloride is a type of semi-synthetic opioid agonist that works as an analgesic (pain reliever).
oxygen: (OK-sih-jen); A colorless, odorless gas. It is needed for animal and plant life. Oxygen that is breathed in enters the blood from the lungs and travels to the tissues.
oxygen radical: (OK-sih-jen RA-dih-kul); A type of unstable molecule that contains oxygen and that easily reacts with other molecules in a cell. A build up of oxygen radicals in cells may cause damage to DNA, RNA, and proteins, and may cause cell death. An oxygen radical is a free radical. Also called reactive oxygen species.
oxygen saturation test: (OK-sih-jen SA-chuh-RAY-shun…); A test that measures the amount of oxygen being carried by red blood cells. One method uses a device that shines light through a finger. The device measures the amount of oxygen in the blood based on the way red blood cells carrying oxygen absorb and reflect light. In another method blood is taken from an artery and the amount of oxygen is measured directly. An oxygen level that is lower than normal may be a sign of lung disease or other medical conditions.
oxygen therapy: (OK-sih-jen THAYR-uh-pee); Treatment in which a storage tank of oxygen or a machine called a compressor is used to give oxygen to people with breathing problems. It may be given through a nose tube, a mask, or a tent. The extra oxygen is breathed in along with normal air. Also called supplemental oxygen therapy.
oxymorphone hydrochloride: (OK-see-MOR-fone HY-droh-KLOR-ide); A drug used to treat moderate to severe pain. Oxymorphone hydrochloride is made in a lab by modifying thebaine, a natural substance found in the opium poppy plant. It works by binding to mu opioid receptors in the central nervous system, which blocks pain signals and changes how the body responds to pain. Oxymorphone hydrochloride is a type of semi-synthetic opioid agonist that works as an analgesic (pain reliever).