Anal Cancer

Treatment for anal cancer depends on many factors, including the location, type and stage of your tumor, as well as your age, health and personal preferences. Your doctor will discuss treatment options in detail with you and design the most effective plan for your condition.

Invasive anal cancer is curable in many patients, particularly when it is diagnosed early and tumors are small. Anal cancers are most commonly treated with a combination of chemotherapy and radiation, which causes tumors to completely regress in 80 to 90 percent of cases.

Surgery may be required for some cancers that do not respond to chemotherapy and radiation, or for those that recur after treatment with chemotherapy and radiation.


Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by pill, or it may be put into the body by a needle in a vein or muscle. Chemotherapy is called a systemic treatment because the drugs enter the bloodstream, travel through the body, and can kill cancer cells throughout the body. Some chemotherapy drugs can also make cancer cells more sensitive to radiation therapy.

Radiation Therapy

Radiation therapy uses X-rays or other high-energy rays to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body, or external radiation therapy, or from putting materials that produce radiation, or radioisotopes, through thin plastic tubes in the area where the cancer cells are found, called internal radiation therapy. Radiation can be used alone or in addition to other treatments.

Side Effects

Patients who receive chemotherapy and radiation therapy experience cumulative side effects that tend to worsen as the therapy continues. Immediate effects may include:

  • Skin reactions with redness around the anus
  • Inflammation of the skin
  • Occasional open sores or ulceration
  • Inflammation and irritation of the gastrointestinal tract, which may cause diarrhea or sores in the mouth, or both
  • Pain and inflammation of the rectum with soreness
  • Sense of urgency or needing to defecate
  • Low blood counts with possible sepsis

Late side effects may include:

  • Skin reactions with formation of scar tissue
  • Anal ulcers that can be quite deep
  • Death of anal tissue or stenosis, or both
  • Narrowing of the anus requiring colostomy in 6 to 12 percent of patients
  • Sterility and sexual dysfunction
  • Small risk of treatment-related leukemia, usually thought to be related to the therapy, mitomycin


In some cases, a surgical procedure called local excision may be used for select small anal tumors. This procedure is only recommended for small tumors that have not spread to other areas. During this procedure, the tumor is removed from the anus along with some surrounding healthy tissue. The sphincter muscle is not removed so that patients still have control over their bowel movements after surgery.

For other cases in which the tumor does not respond to chemotherapy and radiation, or for cases in which the tumor comes back after an apparent initial response, an operation called abdominoperineal resection may be required. During this surgery, an incision is made in the abdomen through which the anus, rectum, part of the colon and any lymph nodes containing cancer are removed.

The doctor then brings the end of the colon to the surface of the abdomen to create an artificial opening, called a colostomy. The colostomy serves as a substitute anus allowing the passage of body waste directly from the colon into a disposable bag outside the body. Our specially trained nurses will help you learn how to manage your colostomy and incorporate it into your lifestyle.

Reviewed by health care specialists at UCSF Medical Center.