Anal Cancer

Treatment

At Mayo Clinic, chemotherapy, radiation therapy and surgery are used to treat anal cancer. Several forms of radiation therapy, including intraoperative radiation therapy (IORT) and intensity-modulated radiation therapy (IMRT), may be used. Treatment may also include biological therapy.

Chemotherapy

Chemotherapy drugs destroy cancer cells, alone or with radiation therapy. Chemotherapy and radiation given together is the most common treatment for cancer that has not spread beyond the anus. If the cancer has spread to other body parts, chemotherapy may also be recommended.

Radiation Therapy

The goal of radiation is to destroy cancer cells while minimizing the damage to surrounding tissue. Physicians typically recommend radiation in combination with chemotherapy for treatment of early stage anal cancer. To treat anal cancer, radiation therapy is delivered in several ways. The length of radiotherapy and type of chemotherapy depends on the specifics of each case.

Intensity-Modulated Radiation Therapy

External beam therapy delivers radiation by a beam from a large machine placed over the body. A new external beam therapy known as intensity-modulated radiation therapy (IMRT) uses precisely shaped radiation beams to accurately deliver high-dose treatment. IMRT yields positive outcomes with fewer side effects than older forms of external radiation therapy.

Intraoperative Radiation Therapy

Intraoperative radiation therapy (IORT) delivers a concentrated beam of radiation to cancerous tumors while they are exposed during surgery. This technique allows doctors to administer high doses of radiation to tumors without exposing nearby healthy organs to radiation. A single dose of intraoperative radiation may have as much effect on the tumor as 10 to 20 daily radiation treatments. The form of IORT most commonly used at Mayo Clinic also is called intraoperative electron radiation therapy, or IOERT. Mayo Clinic's IORT program, which began in 1981, is one of the world's largest.

Surgery

Surgeons use several techniques to remove the cancer:

In local resection, the surgeon removes the cancer and a small amount of adjacent healthy tissue. This procedure can often be used when physicians diagnose the cancer early. Often the ring of muscle around the anus that opens and closes (the sphincter) can be saved during surgery so that it is possible to pass body wastes the same way as prior to the diagnosis of anal cancer.

In abdominoperineal resection, the surgeon removes the anus and the lower part of the rectum and creates an opening (stoma) on the outside of the body to pass waste. This artificial anus is known as a colostomy. Lymph nodes may also be taken out then or in a separate surgery.

Biological Therapy

Biological therapy, also called immunotherapy, uses the body's immune system to fight cancer. The immune system finds cancer cells in the body and works to destroy them. Biological therapies may be used to repair, stimulate or enhance the immune system's natural anticancer function. These therapies may be combined with other treatments.