Anal Cancer Treatment

Anal cancer is a type of cancer that forms in the tissues of the anus.

The anus is the end of the large intestine. It is where stool (solid waste) leaves the body. The anus is formed partly from the outer skin layers of the body and partly from the intestine. The anus is connected to the rectum by the anal canal, which is about 1 to 1½ inches long. This area is controlled by two ring-like sphincter muscles, which contract to hold stool in and relax to allow its passage out of the body.

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Anatomy of the lower gastrointestinal (digestive) system showing the colon, rectum, and anus. Other organs that make up the digestive system are also shown.

Anal cancer can start in the lining of the anal canal, called the mucosa, or in the perianal skin, the squamous cells outside of the anus that contain hair follicles and sweat glands.

Tumors of the perianal skin that do not involve the anal sphincter are usually treated the same as anal cancers, although local therapy (treatment directed to a limited area of skin) may be used for some.

Most anal cancers are related to human papillomavirus (HPV) infection.

Anal cancer is caused by certain changes to the way anal cells function, especially how they grow and divide into new cells. A risk factor is anything that increases the chance of getting a disease. Some risk factors for anal cancer can be changed. However, risk factors also include things people cannot change, like their genetics, getting older, and their health history.

There are many risk factors for anal cancer, but many do not directly cause cancer. Instead, they increase the chance of DNA damage in cells that may lead to anal cancer. To learn more about how cancer develops, see What Is Cancer?

Having one or more of these risk factors does not mean that you will get anal cancer. Many people with risk factors never develop anal cancer, while others with no known risk factors do.

Risk factors for anal cancer include:

• being infected with a high-risk human papillomavirus (HPV), especially HPV type 16 or 18. Learn more about HPV and Cancer.
• having a condition or disease that causes a weakened immune system, such as HIV or an organ transplant
• having a personal history of vulvar, vaginal, or cervical cancers
• having many sexual partners
• having receptive anal intercourse (anal sex)
• smoking cigarettes. Learn more about Tobacco (includes help with quitting).

Talk with your doctor if you think you may be at risk.

Signs of anal cancer include bleeding from the anus or rectum or a lump near the anus.

These and other signs and symptoms may be caused by anal cancer or by other conditions. Check with your doctor if you have:

• bleeding from the anus or rectum
• a lump near the anus
• pain or pressure in the area around the anus
• itching or discharge from the anus
• a change in bowel habits

Tests that examine the rectum and anus are used to diagnose anal cancer.

In addition to asking about your personal and family health history and doing a physical exam, your doctor may perform the following tests and procedures:

• Digital rectal examination (DRE) is 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.
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  Digital rectal exam (DRE). The doctor inserts a gloved, lubricated finger into the rectum and feels the rectum, anus, and prostate (in males) to check for anything abnormal.
  

• Anoscopy is an exam of the anus and lower rectum using a short, lighted tube called an anoscope.
• Proctoscopy is a procedure to look inside the rectum and anus to check for abnormal areas, using a proctoscope. A proctoscope is a thin, tube-like instrument with a light and a lens for viewing the inside of the rectum and anus. It may also have a tool to remove tissue samples, which are checked under a microscope for signs of cancer.
• Endo-anal or endorectal ultrasound is 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 is 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.

After anal cancer has been diagnosed, tests are done to find out if cancer cells have spread within the anus or to other parts of the body.

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 this 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) uses a computer linked to an x-ray machine to make a series of detailed pictures of areas inside the body, such as the abdomen, pelvis, or chest. The pictures are taken from different angles and are used to create 3-D views of tissues and organs. 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.
• Chest x-ray is a type of radiation that can go through the body and make pictures of the organs and bones inside the chest.
• MRI (magnetic resonance imaging) is 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) uses a small amount of radioactive glucose that is injected into a vein. The PET scanner rotates around the body and makes pictures of where glucose is being used in the body. Cancer cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
• Pelvic exam is an exam of the vagina, cervix, uterus, fallopian tubes, ovaries, and rectum. A speculum is inserted into the vagina and the doctor or nurse looks at the vagina and cervix for signs of disease. A Pap test of the cervix is usually done. The doctor or nurse also inserts one or two lubricated, gloved fingers of one hand into the vagina and places the other hand over the lower abdomen to feel the size, shape, and position of the uterus and ovaries. The doctor or nurse also inserts a lubricated, gloved finger into the rectum to feel for lumps or abnormal areas.
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  Pelvic exam. A doctor or nurse inserts one or two lubricated, gloved fingers of one hand into the vagina and presses on the lower abdomen with the other hand. This is done to feel the size, shape, and position of the uterus and ovaries. The vagina, cervix, fallopian tubes, and rectum are also checked.
  

Some people decide to get a second opinion.

You may want to get a second opinion to confirm your anal cancer diagnosis and treatment plan. If you seek a second opinion, you will need to get medical test results and reports from the first doctor to share with the second doctor. The second doctor will review the pathology report, slides, and scans. They may agree with the first doctor, suggest changes or another treatment approach, or provide more information about your cancer.

Learn more about choosing a doctor and getting a second opinion at Finding Cancer Care. You can contact NCI’s Cancer Information Service via chat, email, or phone (both in English and Spanish) for help finding a doctor, hospital, or getting a second opinion. For questions you might want to ask at your appointments, visit Questions to Ask Your Doctor about Cancer.

Certain factors affect the prognosis (chance of recovery) and treatment options.

The prognosis depends on:

• the size of the tumor
• whether the cancer has spread to the lymph nodes

The treatment options depend on:

• the stage of the cancer
• where the tumor is in the anus
• whether the person has HIV
• whether cancer remains after initial treatment or has recurred (come back)

The following stages are used for anal cancer:

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Tumor sizes are often measured in centimeters (cm) or inches. Common food items that can be used to show tumor size in cm include: a pea (1 cm), a peanut (2 cm), a grape (3 cm), a walnut (4 cm), a lime (5 cm or 2 inches), an egg (6 cm), a peach (7 cm), and a grapefruit (10 cm or 4 inches).

Anal cancer can recur (come back) after it has been treated.

Recurrent anal cancer is cancer that has come back after it has been treated. If anal cancer comes back, it may come back in the anus or in other parts of the body, such as the liver or lungs. Tests will be done to help determine where the cancer has returned. The type of treatment for recurrent anal cancer will depend on where it has come back.

Learn more in Recurrent Cancer: When Cancer Comes Back. Information to help you cope and talk with your health care team can be found in the booklet When Cancer Returns.

There are different types of treatment for people with anal cancer.

Different types of treatments are available for anal cancer. You and your cancer care team will work together to decide your treatment plan, which may include more than one type of treatment. Many factors will be considered, such as the stage of the cancer, your overall health, and your preferences. Your plan will include information about your cancer, the goals of treatment, your treatment options and the possible side effects, and the expected length of treatment. 

Talking with your cancer care team before treatment begins about what to expect will be helpful. You’ll want to learn what you need to do before treatment begins, how you’ll feel while going through it, and what kind of help you will need. To learn more, visit Questions to Ask Your Doctor about Treatment. 

The following types of treatment are used:

New types of treatment are being tested in clinical trials.

For some people, joining a clinical trial may be an option. There are different types of clinical trials for people with cancer. For example, a treatment trial tests new treatments or new ways of using current treatments. Supportive care and palliative care trials look at ways to improve quality of life, especially for those who have side effects from cancer and its treatment.

You can use the clinical trial search to find NCI-supported cancer clinical trials accepting participants. The search allows you to filter trials based on the type of cancer, your age, and where the trials are being done. Clinical trials supported by other organizations can be found on the ClinicalTrials.gov website.

Learn more about clinical trials, including how to find and join one, at Clinical Trials Information for Patients and Caregivers.

This summary section describes treatments that are being studied in clinical trials. It may not mention every new treatment being studied.

Treatment for anal cancer may cause side effects.

For information about side effects caused by treatment for cancer, visit our Side Effects page.

Follow-up care may be needed.

As you go through treatment, you will have follow-up tests or check-ups. Some tests that were done to diagnose or stage the cancer may be repeated 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).

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This PDQ cancer information summary has current information about the treatment of anal 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.

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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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PDQ® Adult Treatment Editorial Board. PDQ Anal Cancer Treatment. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/types/anal/patient/anal-treatment-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389368]

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