Treatment of Stage IIIA Anal Cancer

The main treatment for stage IIIA anal cancer is a combination of radiation therapy and chemotherapy. External beam radiation therapy (EBRT) is the type of radiation therapy most commonly used for stage IIIA anal cancer. But you might be treated with internal radiation therapy if you cannot tolerate EBRT. Internal radiation therapy may also be given in addition to EBRT.

• External beam radiation therapy (EBRT) - Radiation from a high-energy x-ray machine (linear accelerator) outside the body is focused on the cancer cells. The radiation may focus on some of the pelvis to treat lymph nodes in the groin because anal cancer often spreads to these lymph nodes. EBRT can harm both the cancer cells and nearby healthy tissue. Most people are treated with EBRT for a few minutes 5 days a week for 5 or 6 weeks as an outpatient.

• Internal radiation therapy (brachytherapy or interstitial radiation therapy) - Small pellets (or “seeds”) that contain radioactive materials are placed in your body in or near the tumor. The radioactive pellets release their radiation slowly over time. Brachytherapy lets the doctor use a higher dose of radiation than EBRT. This type of treatment involves a one-time procedure.

If you are treated with chemotherapy, you will probably receive a combination of 5-fluorouracil (5-FU) and mitomycin or 5-FU and cisplatin.

• Adrucil ^® or Efudex ^® (5-fluorouracil or 5-FU) - 5-FU belongs to the group of chemotherapy drugs known as antimetabolites. 5-FU prevents cells from making DNA and RNA, which stops cells from growing. 5-FU is given as a shot in the vein over 5 to 10 minutes or 20 to 60 minutes, or continuously over 22 to 24 hours for 1 to 4 days or longer. The treatment can be repeated every week, every other week, or every 3 weeks. The dose depends on your size and blood counts.

• Mutamycin^® (mitomycin) - Mitomycin belongs to a group of chemotherapy drugs known as antibiotics, but it acts like an alkylating agent. It blocks the cell from making DNA, which results in cell death. Mitomycin is given by an injection in a vein over 20 minutes every 6 to 8 weeks. The dose and how often you get the medicine depend on your weight, your blood counts, how well your kidneys work, and the type of cancer you have.

• Platinol^® (cisplatin) - Cisplatin is a platinum compound chemotherapy drug that acts like an alkylating agent. It stops cancer cells from growing, which kills them. Cisplatin is given by an injection into the vein over at least 1 hour. Your dose depends upon the type of cancer you have, your size, blood counts, and how well your kidneys work.

If you still have some cancerous cells after you finish your radiation and/or chemotherapy treatments, you might have surgery—either a local resection or an abdominoperineal resection.

• Local resection - The surgeon removes only the tumor and a small amount of noncancerous tissue around the tumor. Local resection does not usually affect the muscular ring that opens and closes the anus (sphincter). This means that after the operation, your bowels should be able to move the same way they did before the procedure. 

• Abdominoperineal resection (APR or AP resection) - In this more extensive operation, the surgeon cuts into the abdomen and the space between the anus and the external genitals (perineum) and takes out the anus, rectum, and part of the colon. The surgeon may also take out some of the lymph nodes (small bean-shaped organs that help fight infection) during this operation, which is called lymph node dissection. Lymp node dissection can also be done after APR. Although this surgery used to be the main treatment for anal cancer, many doctors today use a combination of radiation therapy and chemotherapy instead because it is equally effective and does not damage the anal sphincter.
  
  
  • Colostomy (ostomy) - APR damages the anal sphincter. You will need a permanent opening (stoma) in the abdomen so that feces can leave your body. Your surgeon will sew the end of the intestine to this opening. Feces will pass through the colostomy into a disposable collection bag attached to your body.

  This content has been reviewed and approved by Myo Thant, MD.