Anal Cancer Treatment (PDQ®)

As a National Cancer Institute (NCI)-designated Comprehensive Cancer Center, a core part of our mission is to educate patients and the community about cancer. The following summary is trusted information from the NCI.

General Information About Anal Cancer

The anus is the end of the large intestine, below the rectum, through which stool (solid waste) leaves the body. The anus is formed partly from the outer, skin layers of the body and partly from the intestine. Two ring-like muscles, called sphincter muscles, open and close the anal opening to let stool pass out of the body. The anal canal, the part of the anus between the rectum and the anal opening, is about 1½ inches long. Anatomy of the lower digestive system, showing the colon and other organs.

The skin around the outside of the anus is called the perianal area. Tumors in this area are skin tumors, not anal cancer.

Risk factors include the following:

  • Being over 50 years old.
  • Being infected with human papillomavirus (HPV).
  • Having many sexual partners.
  • Having receptive anal intercourse (anal sex).
  • Frequent anal redness, swelling, and soreness.
  • Having anal fistulas (abnormal openings).
  • Smoking cigarettes.

These and other symptoms may be caused by anal cancer. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

  • Bleeding from the anus or rectum.
  • Pain or pressure in the area around the anus.
  • Itching or discharge from the anus.
  • A lump near the anus.
  • A change in bowel habits.

The following tests and procedures may be used:

  • Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
  • Digital rectal examination (DRE): An exam of the anus and 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.
  • Anoscopy: An exam of the anus and lower rectum using a short, lighted tube called an anoscope.
  • Proctoscopy: An exam of the rectum using a short, lighted tube called a proctoscope.
  • Endo-anal or endorectal ultrasound: A procedure in which an ultrasound transducer (probe) is inserted into the anus or 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.
  • Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. If an abnormal area is seen during the anoscopy, a biopsy may be done at that time.

The prognosis (chance of recovery) depends on the following:

  • The size of the tumor.
  • Where the tumor is in the anus.
  • Whether the cancer has spread to the lymph nodes.

The treatment options depend on the following:

Stages of Anal Cancer

The process used to find out if cancer has spread within the anus 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 may be used in the staging process:

  • CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, 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. For anal cancer, a CT scan of the pelvis and abdomen may be done.
  • 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.
  • Endo-anal or endorectal ultrasound: A procedure in which an ultrasound transducer (probe) is inserted into the anus or 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.

In stage 0, abnormal cells are found in the innermost lining of the anus. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

Pea, peanut, walnut, and lime show tumor sizes.

In stage I, cancer has formed and the tumor is 2 centimeters or smaller.

In stage II, the tumor is larger than 2 centimeters.

In stage IIIA, the tumor may be any size and has spread to either:

In stage IIIB, the tumor may be any size and has spread:

  • to nearby organs and to lymph nodes near the rectum; or
  • to lymph nodes on one side of the pelvis and/or groin, and may have spread to nearby organs; or
  • to lymph nodes near the rectum and in the groin, and/or to lymph nodes on both sides of the pelvis and/or groin, and may have spread to nearby organs.

In stage IV, the tumor may be any size andcancer may have spread to lymph nodes or nearby organs and has spread to distant parts of the body.

Recurrent Anal Cancer

Recurrent anal cancer is cancer that has recurred (come back) after it has been treated. The cancer may come back in the anus or in other parts of the body.

Treatment Option Overview

Different types of treatments are available for patients with anal 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.

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.

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 into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.

Cancer therapy can further damage the already weakened immune systems of patients who have the human immunodeficiency virus (HIV). For this reason, patients who have anal cancer and HIV are usually treated with lower doses of anticancer drugs and radiation than patients who do not have HIV.

This summary section describes treatments that are being studied in clinical trials. It may not mention every new treatment being studied. Information about clinical trials is available from the NCI Web site.

Radiosensitizers are drugs that make tumor cells more sensitive to radiation therapy. Combining radiation therapy with radiosensitizers may kill more tumor cells.

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.

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. See the Treatment Options section that follows for links to current treatment clinical trials. These have been retrieved from NCI's listing of clinical trials.

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. This is sometimes called re-staging.

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.

Treatment Options by Stage

A link to a list of current clinical trials is included for each treatment section. For some types or stages of cancer, there may not be any trials listed. Check with your doctor for clinical trials that are not listed here but may be right for you.

Stage 0 (Carcinoma in Situ)

Treatment of stage 0 is usually local resection.

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with stage 0 anal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

Stage I Anal Cancer

Treatment of stage I anal cancer may include the following:

Patients who have had treatment that saves the sphincter muscles may receive follow-up exams every 3 months for the first 2 years, including rectal exams with endoscopy and biopsy, as needed.

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with stage I anal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

Stage II Anal Cancer

Treatment of stage II anal cancer may include the following:

Patients who have had treatment that saves the sphincter muscles may receive follow-up exams every 3 months for the first 2 years, including rectal exams with endoscopy and biopsy, as needed.

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with stage II anal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

Stage IIIA Anal Cancer

Treatment of stage IIIA anal cancer may include the following:

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with stage IIIA anal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

Stage IIIB Anal Cancer

Treatment of stage IIIB anal cancer may include the following:

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with stage IIIB anal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

Stage IV Anal Cancer

Treatment of stage IV anal cancer may include the following:

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with stage IV anal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

Treatment Options for Recurrent Anal Cancer

Treatment of recurrent anal cancer may include the following:

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with recurrent anal cancer. For more specific results, refine the search by using other search features, such as the location of the trial, the type of treatment, or the name of the drug. General information about clinical trials is available from the NCI Web site.

To Learn More About Anal Cancer

For more information from the National Cancer Institute about anal cancer, see the following:

For general cancer information and other resources from the National Cancer Institute, see the following:



Cancer Care Services

Clinical Trials