Treatment of Anal Cancer, by Stage

The type of treatment your cancer care team will recommend depends on the type of anal cancer, where it is, and how far it has spread (the stage).

Perianal tumors (previously called anal margin cancers) are sometimes treated differently from anal canal cancers.

Stage 0

At this stage, the pre-cancer cells are still only in the inner lining of the anus and have not grown into deeper layers.

Stage 0 tumors can often be removed completely by surgery (local resection). The goal is to take out all of the pre-cancer as well as an edge (margin) of healthy tissue around it. Radiation therapy and chemotherapy (chemo) are rarely needed.

Stages I and II

These cancers have grown into the anal wall but have not grown into nearby organs or spread to nearby lymph nodes.

Surgery (local resection) might be used to remove some small tumors (usually less than 2 centimeter or 1 inch) that do not involve the sphincter muscle. In some cases, this may be followed with chemo and radiation therapy.

The standard treatment for anal cancers that cannot be removed without harming the anal sphincter is external beam radiation therapy (EBRT) combined with chemo (called chemoradiation). In chemoradiation, the 2 treatments are given over the same time period. The chemo is usually 5-FU with mitomycin. This combination of chemo is typically given during the first week and around the fifth week of treatment. The EBRT is given daily, Monday through Friday, for 5 to 7 weeks. 

If the cancer hasn’t gone away completely after chemoradiation is done, more treatment might be needed. But it's important to know that it may take months to see the full effects of chemoradiation. Because of this, it is important to continue follow-up appointments with your doctors to monitor the cancer through digital rectal examination and anoscopy.  Your doctors may watch any remaining cancer for up to 6 months. It may continue to shrink and even go away without more treatment.

At 6 months, if cancer is still found, more treatment is often needed. Most of the time, a surgery called an abdominoperineal resection (APR) might be recommended. In certain cases, only a local resection might be needed.

Stages IIIA, IIIB, and IIIC

These cancers have grown into nearby organs or spread to nearby lymph nodes, but they have not spread to distant parts of the body.

In most cases, the first treatment will be radiation therapy combined with chemo (chemoradiation). In chemoradiation, both treatments are given over the same time period. The chemo is usually 5-FU with mitomycin. This combination of chemo is typically given during the first week and then around the fifth week of treatment. The radiation is given daily, Monday through Friday, for 5 to 7 weeks. 

If some cancer remains after the chemoradiation, it may be watched closely for up to 6 months because it can take months to see the full effects of treatment.

If more treatment is needed because all of the cancer has not gone away by 6 months, most often a surgery called an abdominoperineal resection (APR) might be recommended. If the cancer has spread to or is still present in nearby lymph nodes, they may be removed with surgery or treated with radiation therapy.

Stage IV

In this stage, the cancer has spread to distant organs. Most often, anal cancer first spreads to the liver, but it can also spread to places such as the lungs, bones, and far away lymph nodes.

Treatment is very unlikely to cure these cancers. Instead, treatment is aimed at controlling the disease for as long as possible and relieving symptoms as much as possible. Chemotherapy, sometimes along with radiation, is usually the standard treatment.

Radiation might be used alone for cancer that has spread to the bones, brain or spinal cord. It might also be used for cancer that has spread to far away lymph nodes.

For some advanced anal cancers that have grown on chemotherapy, immunotherapy might be an option.

Because these cancers can be hard to treat, you might also want to think about taking part in a clinical trial of newer treatments.

Recurrent anal cancer

Cancer is called recurrent when it comes back after treatment. Recurrence can be local (in or near the same place it started) or distant (spread to organs like the lungs or liver).

If cancer returns in the anus or nearby lymph nodes after treatment, treatment depends on what treatment you had the first time. For example, if you had surgery alone, you may get radiation therapy and chemo (chemoradiation). If you first had chemoradiation, then you might be treated with surgery and/or chemo. Treating recurrent anal cancer often requires a surgery called an abdominoperineal resection (APR).

For some people, the cancer will come back in distant sites or organs in the body. The most common sites are the liver and lungs. The main treatment for this is usually chemo. Chemo might not cure the cancer, but it can often help control it and reduce any symptoms it's causing. In other cases, surgery or radiation therapy might be options to help treat these cancers. But as with chemo, they are unlikely to cure these cancers, so be sure you understand the goal of any treatments offered.

Clinical trials of newer treatments might also be useful for people with recurrent anal cancer.

Treating HIV-infected patients

Most people with HIV infection can be given the same treatment as others with anal cancer, and they can have a good outcome. People with advanced HIV disease and weakened immune systems might need to have less intensive chemotherapy.

Anal melanoma

Melanoma doesn’t respond well to chemotherapy or radiation, so surgery to remove the cancer is the main treatment when possible. Early stage anal melanomas are treated with surgery to remove the tumor and a rim of surrounding normal tissue (local excision). If the tumor is large or has grown into deeper tissues (such as the sphincter muscle) a bigger operation, such as an abdominoperineal resection (APR) might be needed.

If the melanoma has spread to other organs, it's treated like skin melanoma that has spread, often with immunotherapy or targeted therapy drugs. For more information about the treatment of advanced melanoma, see Treating Melanoma Skin Cancer.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Czito BG, Ahmed S, Kalady MF, and Eng C. Chapter 64: Cancer of the anal region. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles & Practice of Oncology. 11th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2019.

Goodman KA, Kachnic LA, Czito BG. Chapter 76: Cancer of the anal canal. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa. Elsevier: 2020.

National Cancer Institute Physician Data Query (PDQ). Anal Cancer Treatment. 2020. Updated January 22, 2020. Accessed at https://www.cancer.gov/types/anal/hp/anal-treatment-pdq#_1 on March 24, 2020.

National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Anal Carcinoma. V.1.2020. Accessed at www.nccn.org/professionals/physician_gls/pdf/anal.pdf on March 24, 2020.

Ryan DP and Willett CG. Treatment of Anal Cancer. Goldberg RM ed. UpToDate. Waltham, MA: UpToDate Inc. https://www.uptodate.com (Accessed on March 24, 2020.)

Last Revised: September 9, 2020

American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.