Colon/Rectal Cancer (Colorectal Carcinoma)

Cancer of the colon and rectum is the second most common malignancy in the United States (surpassed only by lung cancer), with about 138,000 new cases and 55,000 deaths a year. Even so, death rates from colorectal cancer have fallen by 29 percent in men and 7 percent in women over the past 30 years, and recent progress promises further reductions in mortality.

It is now known that a single gene is responsible for about one in every seven colon cancers. Other risk factors include the presence of colon polyps, inflammatory bowel disease, and certain other kinds of cancer, especially of the breast, uterus, and ovaries.

Diagnostic Studies and Procedures

Since the gene responsible for colon cancer was found by scientists, it has been possible to identify many high-risk people for special preventive care. But procedures are still too complicated and expensive for widespread use. This situation is expected to change soon; researchers are working on a blood test that will identify people with the trait.

In the meantime, the first step in detecting colon or rectal cancer remains an analysis of a stool sample for hidden, or occult, blood, which can come from a polyp or tumor.

Two other screening tests are a digital rectal examination, which should be done every year after age 40, and sigmoidoscopy, in which the rectum and lower sigmoid part of the colon are examined with an optical viewing tube. This test, which should be done every three to five years after age 50, is mildly uncomfortable but not truly painful, especially if a flexible rather than rigid instrument is used; most doctors now use flexible versions of the sigmoidoscope.

If colon or rectal cancer is suspected on the basis of these routine screenings, other laboratory tests and diagnostic procedures will be performed. These usually start with a lower GI series. X-rays in which the intestines are viewed after an infusion of barium, a chalky contrast material. These X-rays will be followed by colonoscopy, a more extensive version of sigmoidoscopy that involves the entire colon. At this time, samples of tissue can be collected for microscopic examination, and small growths can be removed.

If cancer is detected, further studies such as MRI and CT and bone scans may be ordered to see if the disease has spread to other parts of the body.

Medical Treatments

Surgery remains the primary treatment for colorectal cancer. In most cases, the operation involves removal of the cancerous segment plus margins of healthy intestine on both ends. The two ends are then stitched together, allowing normal bowel function after healing. The operation may be followed by a course of chemotherapy and/or radiation treatments, especially if the disease is in an advanced stage.

If cancer involves the lower rectum or anus, an artificial opening, or stoma, may have to be created in the abdominal wall to allow fecal waste to exit the body into a special collection bag.

A colectomy -- surgery to remove the entire colon -- is often recommended for patients who have familial polyposis, because these polyps inevitably develop into an especially lethal form of cancer. Similarly, a colectomy may be necessary for patients with severe inflammatory bowel disease.

In many such cases, a stoma can be avoided with a procedure known as ileoanal anastomosis. In this operation, the rectum is left in place and a segment of small intestine is attached to the rectum just above the anal opening, to assume bowel function.

Even when the entire colon and rectum must be removed, it is sometimes possible to avoid wearing and caring for an external pouch by having a continent ileostomy. This approach involves making an internal collection pouch from the lowermost segment of the small intestine, and creating an opening on the lower abdomen. The pouch can be emptied through a nipple valve with a small tube.

Alternative Therapies

Any form of cancer or precancerous condition needs prompt medical treatment, although alternative therapies can play a supportive role.

Acupuncture. Both acupuncture and acupressure are accepted as useful means of controlling cancer pain.

Nutrition Therapy. No responsible practitioner claims that diet can cure cancer. However, the risk of cancer may be reduced by adhering to a diet that is low in animal fat and high in fiber. Dietary fiber helps prevent constipation by producing soft, bulky stools that pass easily and quickly through the colon. Some studies indicate that this process may also protect against colon cancer. However, if you add more fiber to your diet, do so gradually. A sudden increase may lead to digestive problems.

Recent research suggests that vitamins A, C, and E, as well as calcium, may lower the risk of developing colon cancer, but you should consult a doctor before taking any high-dose supplements, especially if you are undergoing therapy for cancer. In particular, you should avoid taking iron pills, unless they've been prescribed to meet a specific need, because excessive iron is thought to hinder the immune systems defense against cancer.

Yoga and Meditation. These and other relaxation therapies such as visualization and biofeedback can help with reducing the stress, handling the emotions, and managing the pain of cancer.

Self-Treatment

As in all types of cancers, the goal of self-treatment is to maintain a healthful nutritional status and to cooperate as much as possible with medical therapists. The National Cancer Institute recommends the following guidelines to prevent colon cancer:

• Eat fresh or dried fruits for desserts and snacks.
• Make beans, lentils, peas, and other legumes a regular pan of your diet by including them in soups, stews, casseroles, and salads.
• Eat cereals and breads that are made with whole-grain flours.
• Leave the skins on potatoes, fruits, and vegetables to increase fiber intake. Similarly, use brown rice, cracked wheat, and buckwheat instead of white rice and refined grains.
• Consider low-dose aspirin therapy, recent studies indicate that as little as one pill every other day can significantly reduce an individuals risk of developing colon cancer.

During cancer treatment, have frequent small meals that emphasize nutrient-rich foods. Following surgery, a clinical dietitian can help plan menus that minimize demands on the colon until healing is complete.

If a stoma is necessary, an ostomy therapist will provide instruction in its use. Joining an ostomy support group such as those affiliated with the American Cancer Society can be helpful. Ostomy patients find they can lead relatively normal lives, including a return to work and resumption of sexual relations, once they have mastered caring for a stoma.

Other Causes of Blood in the Stool

The presence of blood in the stool is not necessarily an indication of cancer. A positive test result is often due to hemorrhoids, ulcers, polyps, diverticulosis, or other noncancerous conditions.