I am have been cancer-free for more than five years after going through radiation and chemotherapy for a cancerous mass of the colon. Now my problem is that I often bleed from the rectum for about five to 10 minutes after going to the bathroom. I have been rechecked (biopsied) to make sure the cancer hasn't recurred. My doctor says that he is now seeing radiation-related changes in the skin around my anus, but he can't tell me whether the bleeding is going to get better. What is the outlook for people like me? Is there anything I can do to improve this?

S.K.

Rectal bleeding during or just after bowel movements is a relatively common complaint. Explanations for this type of bleeding include hemorrhoids and anal fissures. Rare causes for such bleeding include tumors, polyps or ulcers in the rectum.

Even though rectal bleeding is common, an endoscopic examination of the rectum and colon should be done to rule out serious diagnoses, such as cancer. If caught early, colorectal cancer can be removed by surgery. Sometimes chemotherapy is done for more advanced disease, such as when lymph nodes adjacent to the colon are involved by the tumor. Radiation is often given for locally advanced tumors of the rectum. Once the cancer has been removed and cured, regular screening tests are important to ensure it does not recur.

Patients who have had one colorectal cancer are at higher risk of developing a second, unrelated colorectal tumor at a later time. Thus, it was appropriate in your case to have biopsies done to rule out recurrent cancer. In addition, careful examination of the rest of your colon should also have been done to make sure no new polyps or cancers are developing.

As your doctor mentioned, another potential cause of bleeding in the lower rectum after radiation is the development of changes in the rectum called radiation proctitis. This is a chronic condition, occurring several months after the radiation, in which the inner lining of the rectum develops abnormal blood vessels that bleed easily. The bleeding can be slight or in quantities so large that transfusions are required.

Therapy often initially involves giving stool softeners to prevent constipation, which may aggravate the bleeding. In addition, various suppositories of anti-inflammatory agents and steroids have been used with limited success. Currently, a new therapy involves eliminating these abnormal blood vessels with a heated probe inserted through a colonoscope. This appears to be a very effective and safe way to treat radiation proctitis. To determine the best treatment in your particular case, you should discuss your condition with a gastroenterologist experienced in the treatment of radiation proctitis.