Rectal cancer is a disease in which malignant (cancer) cells
form in the tissues of the rectum.
Health history affects the risk of developing rectal cancer.
Signs of rectal cancer include a change in bowel
habits or blood in the stool.
Tests that examine the rectum and colon are used to diagnose rectal cancer.
Certain factors affect prognosis
(chance of recovery) and treatment options.
Rectal cancer is a disease in which malignant (cancer) cells
form in the tissues of the rectum.
The rectum is part of
the body’s digestive system. The
digestive system takes in nutrients (vitamins, minerals,
carbohydrates, fats, proteins, and water) from foods and helps pass waste
material out of the body. The digestive system is made up of the
esophagus,
stomach, and the
small and
large intestines. The colon (large bowel) is the first part of the large intestine and is about 5 feet long. Together, the rectum and anal canal make up the last part of the large intestine and are 6 to 8 inches long. The anal canal ends at the anus (the opening of the large intestine to the
outside of the body).EnlargeAnatomy of the lower gastrointestinal (digestive) system showing the colon, rectum, and anus. Other organs that make up the digestive system are also shown.
Health history affects the risk of developing rectal cancer.
Anything that increases a person's chance of getting a disease is called a risk factor. Not every person with one or more of these risk factors will develop colorectal cancer, and it will develop in people who don't have any known risk factors. Talk to your doctor if you think you may be at risk for colorectal cancer.
Risk factors for colorectal cancer include the following:
Digital rectal exam (DRE): An exam of the rectum. The doctor or nurse inserts a lubricated, gloved finger into the lower part of the rectum to feel for lumps or anything else that seems unusual. In women, the vagina may also be examined.
Colonoscopy: A procedure to look inside the rectum and colon for polyps (small pieces of bulging tissue), abnormal areas, or cancer. A colonoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove polyps or tissue samples, which are checked under a microscope for signs of cancer.EnlargeColonoscopy. A thin, lighted tube is inserted through the anus and rectum and into the colon to look for abnormal areas.
Biopsy: The removal
of cells or tissues so they can be viewed under a microscope to check for signs of cancer. Tumor tissue that is removed during the biopsy may be checked to see if the patient is likely to have the genemutation that causes HNPCC. This may help to plan treatment.
Immunohistochemistry: A laboratory test that uses antibodies to check for certain antigens (markers) in a sample of a patient’s tissue. The antibodies are usually linked to an enzyme or a fluorescent dye. After the antibodies bind to a specific antigen in the tissue sample, the enzyme or dye is activated, and the antigen can then be seen under a microscope. This type of test is used to help diagnose cancer and to help tell one type of cancer from another type of cancer.
Carcinoembryonic antigen (CEA) assay: A test that measures the level of CEA in the blood. CEA is released into the bloodstream from both cancer cells and normal cells. When found in higher than normal amounts, it can be a sign of rectal cancer or other conditions.
Microsatellite instability (MSI): A laboratory test in which tumor tissue is checked for cells that may have a defect in genes involved in DNA repair. The findings may indicate whether or not the patient has a type of cancer linked to an inherited cancer syndrome such as HNPCC (also known as Lynch syndrome).
Certain factors affect prognosis
(chance of recovery) and treatment options.
The prognosis and treatment options depend on the following:
The
stage of the cancer (whether it
affects the inner lining of the rectum only, involves the whole rectum, or has
spread to lymph nodes, nearby organs, or other places in the body).
Whether the cancer is related to a defect in genes involved in DNA repair.
Whether the tumor has spread into or through the bowel wall.
Where the cancer is found in the rectum.
Whether the bowel is blocked or has a hole in it.
Whether all of the tumor can be removed by surgery.
The patient’s general health.
Whether the cancer has just been diagnosed or has recurred (come back).
Stages of Rectal Cancer
Key Points
After rectal cancer has been diagnosed, tests are done
to find out if cancer cells have spread within the rectum or to other parts of
the body.
There are three ways that cancer spreads in the body.
Cancer may spread from where it began to other parts of the body.
The following stages are used for rectal cancer:
Stage 0 (Carcinoma in Situ)
Stage I
Stage II
Stage III
Stage IV
Rectal cancer can recur (come back) after it has been treated.
After rectal cancer has been diagnosed, tests are done
to find out if cancer cells have spread within the rectum or to other parts of
the body.
The process used to find out whether cancer has spread within the
rectum or to other parts of the body
is called staging. The information gathered from the
staging process determines the stage of the disease. It is important
to know the stage in
order to plan treatment.
The following tests and
procedures may be used in the staging process:
Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
Colonoscopy: A procedure to look inside the rectum and colon for polyps (small pieces of bulging tissue). abnormal areas, or cancer. A colonoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove polyps or tissue samples, which are checked under a microscope for signs of cancer.EnlargeColonoscopy. A thin, lighted tube is inserted through the anus and rectum and into the colon to look for abnormal areas.
CT scan (CAT scan):
A procedure that makes a series of detailed pictures of areas inside the body, such as the abdomen, pelvis, or chest, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
MRI (magnetic
resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
PET scan (positron emission tomography scan): A procedure to find malignanttumorcells in the body. A small amount of radioactiveglucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
Endorectal ultrasound: A procedure used to examine the rectum and nearby organs. An ultrasound transducer (probe) is inserted into the rectum and used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The doctor can identify tumors by looking at the sonogram. This procedure is also called transrectal ultrasound.
There are three ways that cancer spreads in the body.
Tissue. The cancer spreads from where it began by growing into nearby areas.
Lymph system. The cancer spreads from where it began by getting into the lymph system. The cancer travels through the lymph vessels to other parts of the body.
Blood. The cancer spreads from where it began by getting into the blood. The cancer travels through the blood vessels to other parts of the body.
Cancer may spread from where it began to other parts of the body.
When cancer spreads to another part of the body, it is called metastasis. Cancer cells break away from where they began (the primary tumor) and travel through the lymph system or blood.
Lymph system. The cancer gets into the lymph system, travels through the lymph vessels, and forms a tumor (metastatic tumor) in another part of the body.
Blood. The cancer gets into the blood, travels through the blood vessels, and forms a tumor (metastatic tumor) in another part of the body.
The metastatic tumor is the same type of cancer as the primary tumor. For example, if rectal cancer spreads to the lung, the cancer cells in the lung are actually rectal cancer cells. The disease is metastatic rectal cancer, not lung cancer.
Many cancer deaths are caused when cancer moves from the original tumor and spreads to other tissues and organs. This is called metastatic cancer. This animation shows how cancer cells travel from the place in the body where they first formed to other parts of the body.
The following stages are used for rectal cancer:
Stage 0 (Carcinoma in Situ)
EnlargeStage 0 (rectal carcinoma in situ). Abnormal cells are shown in the mucosa of the rectum wall.
EnlargeStage II rectal cancer. In stage IIA, cancer has spread through the muscle layer of the rectum wall to the serosa. In stage IIB, cancer has spread through the serosa but has not spread to nearby organs. In stage IIC, cancer has spread through the serosa to nearby organs.
Stage IIA: Cancer has spread through the muscle layer of the rectum wall to the serosa (outermost layer) of the rectum wall.
Stage IIB: Cancer has spread through the serosa (outermost layer) of the rectum wall to the tissue that lines the organs in the abdomen (visceral peritoneum).
Stage IIC: Cancer has spread through the serosa (outermost layer) of the rectum wall to nearby organs.
EnlargeStage IIIA rectal cancer. Cancer has spread through the mucosa of the rectum wall to the submucosa and may have spread to the muscle layer, and has spread to one to three nearby lymph nodes or tissues near the lymph nodes. OR, cancer has spread through the mucosa to the submucosa and four to six nearby lymph nodes.
through the mucosa (innermost layer) of the rectum wall to the submucosa (layer of tissue next to the mucosa) or to the muscle layer of the rectum wall. Cancer has spread to one to three nearby lymph nodes or cancer cells have formed in tissue near the lymph nodes; or
through the mucosa (innermost layer) of the rectum wall to the submucosa (layer of tissue next to the mucosa). Cancer has spread to four to six nearby lymph nodes.
EnlargeStage IIIB rectal cancer. Cancer has spread through the muscle layer of the rectum wall to the serosa or has spread through the serosa but not to nearby organs; cancer has spread to one to three nearby lymph nodes or to tissues near the lymph nodes. OR, cancer has spread to the muscle layer or to the serosa, and to four to six nearby lymph nodes. OR, cancer has spread through the mucosa to the submucosa and may have spread to the muscle layer; cancer has spread to seven or more nearby lymph nodes.
through the muscle layer of the rectum wall to the serosa (outermost layer) of the rectum wall or has spread through the serosa to the tissue that lines the organs in the abdomen (visceral peritoneum). Cancer has spread to one to three nearby lymph nodes or cancer cells have formed in tissue near the lymph nodes; or
to the muscle layer or to the serosa (outermost layer) of the rectum wall. Cancer has spread to four to six nearby lymph nodes; or
through the mucosa (innermost layer) of the rectum wall to the submucosa (layer of tissue next to the mucosa) or to the muscle layer of the rectum wall. Cancer has spread to seven or more nearby lymph nodes.
EnlargeStage IIIC rectal cancer. Cancer has spread through the serosa of the rectum wall but not to nearby organs; cancer has spread to four to six nearby lymph nodes. OR, cancer has spread through the muscle layer to the serosa or has spread through the serosa but not to nearby organs; cancer has spread to seven or more nearby lymph nodes. OR, cancer has spread through the serosa to nearby organs and to one or more nearby lymph nodes or to tissues near the lymph nodes.
through the serosa (outermost layer) of the rectum wall to the tissue that lines the organs in the abdomen (visceral peritoneum). Cancer has spread to four to six nearby lymph nodes; or
through the muscle layer of the rectum wall to the serosa (outermost layer) of the rectum wall or has spread through the serosa to the tissue that lines the organs in the abdomen (visceral peritoneum). Cancer has spread to seven or more nearby lymph nodes; or
through the serosa (outermost layer) of the rectum wall to nearby organs. Cancer has spread to one or more nearby lymph nodes or cancer cells have formed in tissue near the lymph nodes.
EnlargeStage IV rectal cancer. The cancer has spread through the blood and lymph nodes to other parts of the body, such as the lung, liver, abdominal wall, or prostate.
Stage IVC: Cancer has spread to the tissue that lines the wall of the abdomen and may have spread to other areas or organs.
Rectal cancer can recur (come back) after it has been treated.
The cancer may come back in the
rectum or in other parts of the
body, such as the colon,
pelvis, liver, or lungs.
Treatment Option Overview
Key Points
There are different types of treatment for patients with rectal
cancer.
The following types of treatment are used:
Surgery
Radiation
therapy
Chemotherapy
Active surveillance
Targeted therapy
Immunotherapy
Other types of treatment are being tested in clinical
trials.
Treatment for rectal cancer may cause side effects.
Patients may want to think about taking part in a clinical trial.
Patients can enter clinical trials before, during, or after starting their cancer treatment.
Follow-up tests may be needed.
There are different types of treatment for patients with rectal
cancer.
Different types of treatment are available for patients with
rectal cancer. Some treatments are standard (the currently used treatment), and some
are being tested in clinical trials.
A treatment clinical trial is a research study meant to help
improve current treatments or obtain information on new treatments for patients
with cancer. When clinical trials show that a new treatment is better than the
standard treatment, the new
treatment may become the standard treatment.
Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
The following types of treatment are used:
Surgery
Surgery is the most
common treatment for all stages of rectal cancer. The
cancer is removed using one of the following types of surgery:
Localexcision: If the cancer is found on the inside surface of the rectum and has not spread into the wall of the rectum, the cancer and a small amount of surrounding healthy tissue is removed.
Resection: If
the cancer has spread into the wall of the rectum, the section of the
rectum with cancer and nearby healthy tissue is removed. Sometimes the tissue between the rectum and the abdominal wall is also removed. The lymph nodes near the rectum are removed and checked under a microscope for signs of cancer.
Cryosurgery: A treatment that uses an instrument to freeze and destroy abnormal tissue. This type of treatment is also called cryotherapy.
Pelvic exenteration: If the cancer has spread to other organs near the rectum, the lower colon, rectum, and bladder are removed. In women, the cervix, vagina, ovaries, and nearby lymph nodes may be removed. In men, the prostate may be removed. Artificial openings (stoma) are made for urine and stool to flow from the body to a collection bag.
After the cancer is removed, the surgeon will either:
do an anastomosis (sew the healthy parts of the
rectum together, sew the remaining rectum to the colon, or sew the colon to the
anus);EnlargeResection of the rectum with anastomosis. The rectum and part of the colon are removed, and then the colon and anus are joined. or
make a stoma (an opening) from the rectum to the outside of the body for waste to pass through. This procedure is done if the cancer is too close to the anus and is called
a colostomy. A bag is placed around the stoma to collect the waste. Sometimes the colostomy is needed only until the rectum has
healed, and then it can be reversed. If the entire
rectum is removed, however, the colostomy may be permanent.
Radiation therapy and/or chemotherapy may be given before surgery to shrink the tumor, make it easier to remove the cancer, and help with bowel control after surgery. Treatment given before surgery is called neoadjuvant therapy. After all the cancer that can be seen at the
time of the surgery is removed, some patients may be given radiation therapy and/or chemotherapy after surgery to kill any cancer
cells that are left. Treatment given after the surgery, to lower the risk that the cancer will come back, is called adjuvant
therapy.
Radiation
therapy
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. External radiation therapy uses a machine outside the body to send radiation toward the cancer.
Short-course preoperative radiation therapy is used in some types of rectal cancer. This treatment uses fewer and lower doses of radiation than standard treatment, followed by surgery several days after the last dose.
Chemotherapy
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly in the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy).
Chemoembolization of the hepatic artery is a type of regional chemotherapy that may be used to treat cancer that has spread to the liver. This is done by blocking the hepatic artery (the main artery that supplies blood to the liver) and injecting anticancer drugs between the blockage and the liver. The liver’s arteries then carry the drugs into the liver. Only a small amount of the drug reaches other parts of the body. The blockage may be temporary or permanent, depending on what is used to block the artery. The liver continues to receive some blood from the hepatic portal vein, which carries blood from the stomach and intestine.
The way the chemotherapy is given depends on the type and stage of the cancer being treated.
Active surveillance is closely following a patient's condition without giving any treatment unless there are changes in test results. It is used to find early signs that the condition is getting worse. In active surveillance, patients are given certain exams and tests to check if the cancer is growing. When the cancer begins to grow, treatment is given to cure the cancer. Tests include the following:
Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells.
Types of targeted therapies used in the treatment of rectal cancer include the following:
Monoclonal antibodies: Monoclonal antibodies are immune systemproteins made in the laboratory to treat many diseases, including cancer. As a cancer treatment, these antibodies can attach to a specific target on cancer cells or other cells that may help cancer cells grow. The antibodies are able to then kill the cancer cells, block their growth, or keep them from spreading. Monoclonal antibodies are given by infusion. They may be used alone or to carry drugs, toxins, or radioactive material directly to cancer cells.
There are different types of monoclonal antibody therapy:
Epidermal growth factor receptor (EGFR) inhibitor therapy: EGFRs are proteins found on the surface of certain cells, including cancer cells. Epidermal growth factor attaches to the EGFR on the surface of the cell and causes the cells to grow and divide. EGFR inhibitors block the receptor and stop the epidermal growth factor from attaching to the cancer cell. This stops the cancer cell from growing and dividing. Cetuximab and panitumumab are EGFR inhibitors.
How do monoclonal antibodies work to treat cancer? This video shows how monoclonal antibodies, such as trastuzumab, pembrolizumab, and rituximab, block molecules cancer cells need to grow, flag cancer cells for destruction by the body’s immune system, or deliver harmful substances to cancer cells.
Angiogenesis inhibitors: Angiogenesis inhibitors stop the growth of new blood vessels that tumors need to grow.
Regorafenib is used to treat colorectal cancer that has spread to other parts of the body and has not gotten better with other treatment. It blocks the action of certain proteins, including vascular endothelial growth factor. This 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.
Protein kinase inhibitor therapy: This treatment blocks a protein needed for cancer cells to divide. Protein kinase inhibitors include:
Immunotherapy is a treatment that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against cancer.
Immune checkpoint inhibitor therapy: Immune checkpoint inhibitors block proteins called checkpoints that are made by some types of immune system cells, such as T cells, and some cancer cells. These checkpoints help keep immune responses from being too strong and sometimes can keep T cells from killing cancer cells. When these checkpoints are blocked, T cells can kill cancer cells better. They are used to treat some patients with metastatic colorectal cancer.
There are two types of immune checkpoint inhibitor therapy:
CTLA-4 inhibitor therapy: CTLA-4 is a protein on the surface of T cells that helps keep the body’s immune responses in check. When CTLA-4 attaches to another protein called B7 on a cancer cell, it stops the T cell from killing the cancer cell. CTLA-4 inhibitors attach to CTLA-4 and allow the T cells to kill cancer cells. Ipilimumab is a type of CTLA-4 inhibitor. EnlargeImmune checkpoint inhibitor. Checkpoint proteins, such as B7-1/B7-2 on antigen-presenting cells (APC) and CTLA-4 on T cells, help keep the body’s immune responses in check. When the T-cell receptor (TCR) binds to antigen and major histocompatibility complex (MHC) proteins on the APC and CD28 binds to B7-1/B7-2 on the APC, the T cell can be activated. However, the binding of B7-1/B7-2 to CTLA-4 keeps the T cells in the inactive state so they are not able to kill tumor cells in the body (left panel). Blocking the binding of B7-1/B7-2 to CTLA-4 with an immune checkpoint inhibitor (anti-CTLA-4 antibody) allows the T cells to be active and to kill tumor cells (right panel).
PD-1 and PD-L1 inhibitor therapy: PD-1 is a protein on the surface of T cells that helps keep the body’s immune responses in check. PD-L1 is a protein found on some types of cancer cells. When PD-1 attaches to PD-L1, it stops the T cell from killing the cancer cell. PD-1 and PD-L1 inhibitors keep PD-1 and PD-L1 proteins from attaching to each other. This allows the T cells to kill cancer cells. Pembrolizumab and nivolumab are types of PD-1 inhibitors. Dostarlimab is a PD-1 inhibitor being studied in clinical trials.
EnlargeImmune checkpoint inhibitor. Checkpoint proteins, such as PD-L1 on tumor cells and PD-1 on T cells, help keep immune responses in check. The binding of PD-L1 to PD-1 keeps T cells from killing tumor cells in the body (left panel). Blocking the binding of PD-L1 to PD-1 with an immune checkpoint inhibitor (anti-PD-L1 or anti-PD-1) allows the T cells to kill tumor cells (right panel).
Immunotherapy uses the body’s immune system to fight cancer. This animation explains one type of immunotherapy that uses immune checkpoint inhibitors to treat cancer.
Patients may want to think about taking part in a clinical trial.
For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.
Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.
Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.
Patients can enter clinical trials before, during, or after starting their cancer treatment.
Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.
Clinical trials are taking place in many parts of the country. Information about clinical trials supported by NCI can be found on NCI’s clinical trials search webpage. Clinical trials supported by other organizations can be found on the ClinicalTrials.gov website.
Follow-up tests may be needed.
Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.
Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.
After treatment for rectal cancer, a blood test to measure amounts of
carcinoembryonic antigen (a
substance in the blood that may be increased when cancer is present) may be
done to see if the cancer has come back.
Resection (when the tumor is too large to remove by local excision).
Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.
Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.
Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.
Placement of a stent to help keep the rectum open if it is partly blocked by the tumor, as palliative therapy to relieve symptoms and improve the quality of life.
A clinical trial of chemoembolization combined with radiation therapy to the tumors in the liver.
Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done. General information about clinical trials is also available.
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Purpose of This Summary
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Clinical trials can be found online at NCI's website. For more information, call the Cancer Information Service (CIS), NCI's contact center, at 1-800-4-CANCER (1-800-422-6237).
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