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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 6-8 inches long. The anal canal ends at the anus (the opening of the large intestine to the outside of the body).Anatomy of the lower digestive system, showing the colon and other organs.
See the following PDQ summaries for more information about rectal cancer:
Health history affects the risk of developing rectal cancer.
Anything that increases your chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk to your doctor if you think you may be at risk for colorectal cancer.
Risk factors for colorectal cancer include the following:
Older age is a main risk factor for most cancers. The chance of getting cancer increases as you get older.
Signs of rectal cancer include a change in bowel habits or blood in the stool.
These and other signs and symptoms may be caused by rectal cancer or by other conditions. Check with your doctor if you have any of the following:
Tests that examine the rectum and colon are used to detect (find) and diagnose rectal cancer.
Tests used to diagnose rectal cancer include the following:
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options depend on the following:
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:
There are three ways that cancer spreads in the body.
Cancer can spread through tissue, the lymph system, and the blood:
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.
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.
The following stages are used for rectal cancer:
Stage 0 (Carcinoma in Situ)
Stage 0 (rectal carcinoma in situ). Abnormal cells are shown in the mucosa of the rectum wall.
In stage 0 rectal cancer, abnormal cells are found in the mucosa (innermost layer) of the rectum wall. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.
Stage I rectal cancer. Cancer has spread from the mucosa of the rectum wall to the submucosa or to the muscle layer.
In stage I rectal cancer, cancer has formed in the mucosa (innermost layer) of the rectum wall and has spread to the submucosa (layer of tissue next to the mucosa) or to the muscle layer of the rectum wall.
Stage 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 II rectal cancer is divided into stages IIA, IIB, and IIC.
Stage III rectal cancer is divided into stages IIIA, IIIB, and IIIC.
Stage 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.
In stage IIIA, cancer has spread:
Stage 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.
In stage IIIB, cancer has spread:
Stage 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.
In stage IIIC, cancer has spread:
Stage IV rectal cancer is divided into stages IVA, IVB, and IVC.
Stage 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 ovary.
Recurrent rectal cancer is cancer that has recurred (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.
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.
Six types of standard treatment are used:
Surgery is the most common treatment for all stages of rectal cancer. The cancer is removed using one of the following types of surgery:
After the cancer is removed, the surgeon will either:
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 is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy:
The way the radiation therapy is given depends on the type and stage of the cancer being treated. External radiation therapy is used to treat rectal 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 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.
See Drugs Approved for Colon and Rectal Cancer for more information.
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 without harming normal cells.
Types of targeted therapies used in the treatment of rectal cancer include the following:
There are different types of monoclonal antibody therapy:
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. This type of cancer treatment is also called biotherapy or biologic therapy.
Immune checkpoint inhibitor therapy is a type of immunotherapy:
Immune 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).
Other types of treatment are being tested in clinical trials.
Information about clinical trials is available from the NCI website.
Treatment for rectal cancer may cause side effects.
For information about side effects caused by treatment for cancer, see our Side Effects page.
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.
For information about the treatments listed below, see the Treatment Option Overview section.
Stage 0 (Carcinoma in Situ)
Treatment of stage 0 may include the following:
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.
Stage I Rectal Cancer
Treatment of stage I rectal cancer may include the following:
Stages II and III Rectal Cancer
Treatment of stage II and stage III rectal cancer may include the following:
Stage IV and Recurrent Rectal Cancer
Treatment of stage IV and recurrent rectal cancer may include the following:
Treatment of rectal cancer that has spread to other organs depends on where the cancer has spread.
For more information from the National Cancer Institute about rectal cancer, see the following:
For general cancer information and other resources from the National Cancer Institute, see the following:
Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.
PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government's center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.
Purpose of This Summary
This PDQ cancer information summary has current information about the treatment of rectal cancer. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.
Reviewers and Updates
Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Updated") is the date of the most recent change.
The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Adult Treatment Editorial Board.
Clinical Trial Information
A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." 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.
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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The best way to cite this PDQ summary is:
PDQ® Adult Treatment Editorial Board. PDQ Rectal Cancer Treatment. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/types/colorectal/patient/rectal-treatment-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389378]
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Last Revised: 2019-05-16
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