Surgery for anal cancer involves removing the cancer using a local resection or an abdominoperineal resection. The specific procedure will depend on the size and location of the tumor. Local resection removes the cancer only and is usually done when the cancer has not spread to nearby tissues or lymph nodes. The sphincter, or the muscle that opens and closes the anus, is not removed in most local resections.

Abdominoperineal surgeries are not performed very often since radiation therapy with chemotherapy is equally effective for eliminating cancer cells and does not require a colostomy.

An abdominoperineal resection, when necessary, may be performed on patients whose cancer has spread beyond the anus and did not respond well to radiation with chemotherapy. During this procedure, the doctor removes the anus and the lower part of the rectum by cutting into the abdomen and the perineum (the space between the anus and the scrotum in men or the anus and the vulva in women). A hole, or stoma, is made on the outside of the body so that the patient will be able to pass waste. This is called a colostomy. The patient will wear a bag outside the body to collect waste. The bag, which sticks to the skin around the stoma with special glue, is thrown away after use.

Surgery may also involve a lymph-node dissection, a procedure in which lymph nodes are removed.

Radiation therapy uses high-energy rays such as X-rays to kill cancer cells and shrink tumors. In external radiation therapy, the rays come from a machine outside the body. In internal radiation therapy, radioactive material is implanted in the area where the cancer cells are found. Both methods of radiation therapy may be used together, and radiation therapy can be given alone or in combination with other therapies.

Side effects of radiation include fatigue and a burn or a darkening of the pigment in the skin of the treated area. Side effects usually disappear six to 12 months after treatment.

Chemotherapy uses powerful drugs to kill cancer cells or sensitize cancer cells to radiation therapy. The chemotherapy drugs are generally given intravenously. In almost all cases, chemotherapy and radiation therapy are used together to maximize the chance that the cancer will be killed completely. In this case, an abdominoperineal resection may not be necessary and the anal sphincter can be preserved. The main chemotherapy drugs used to treat anal cancer are 5-fluorouracil (5-FU) and mitomycin C. Recent trials have also examined the combination of 5-FU and cisplatin together with radiation therapy.

Chemotherapy drugs enter the system and travel through the bloodstream killing cancer cells throughout the body. However, the drugs can also harm non-cancerous cells. Damage to certain types of cells can cause fatigue, nausea, hair loss and greater susceptibility to infection.

Stage 0: Surgery to remove all of the cancer.

Stage I: Surgery (if the sphincter can be preserved) or radiation therapy with chemotherapy. If cancer cells remain following treatment with chemotherapy and radiation, surgery may involve removing the anus and lower part of the rectum. Additional chemotherapy and radiation therapy may be given.

Stage II: Radiation therapy and chemotherapy are the primary treatments. If cancer cells remain following therapy, a doctor may remove the anus and lower part of the rectum or provide additional radiation therapy.

Stage IIIA: Radiation plus chemotherapy followed by surgery.

IIIB: Radiation therapy plus chemotherapy followed by surgery. The type of surgery depends on how much cancer remains following chemotherapy and radiation. Lymph nodes in the groin area may be removed during surgery.

Stage IV: Surgery, radiation, chemotherapy or a combination of treatments may be given to relieve symptoms caused by the cancer. Patients may also enroll in a clinical trial testing new treatments.

Recurrent: The choice of treatment depends on which treatment the patient received previously. If surgery was used the first time, a doctor may choose radiation therapy.