The main treatment for cancer of the anal canal is a combination of radiotherapy and chemotherapy. Surgery is usually only used if this treatment does not completely get rid of all of the cancer or if the cancer comes back after treatment.

The anus is the muscular area at the end of the large bowel. It includes the muscle, which opens and closes to control bowel movements, and is where the bowel opens to the outside.

An operation to remove a cancer of the anal canal has to take away the whole of the anal canal to be sure of clearing the cancer. This means removing muscle that controls bowel movements. This is called an abdominoperineal resection. After this type of surgery the open end of the bowel is brought out on to the front of the tummy to allow faeces to be passed out of the body into a colostomy bag.

In most situations, giving radiotherapy, together with chemotherapy, offers an equally good chance of cure but avoids the need for a colostomy.

Reference

• Clark M et al. Cancer of the anal canal. 2004 Lancet Oncology 5(3);149-157.