Colon cancer: common and curable

Symptoms are slow to evolve

"Colon cancer often causes no symptoms until it has advanced to a more serious stage, at which point, treatment becomes more difficult and, unfortunately, possibly unsuccessful," explains Dr. Stanley Rosenberg, a gastroenterologist at Boston's Beth Israel Deaconess Medical Center. Accordingly, he adds that early detection is extremely important to the prevention and successful treatment of colon cancer.

The following symptoms may indicate the presence of colon cancer:

• Chronic abdominal pain
• Rectal bleeding
• Change in bowel habits
• Blood in the stool
• General weakness, or other symptoms of anemia (blood iron deficiency)

Early detection: it can save your life

The presence of any of the symptoms noted above should send you running to your health care provider. Since symptoms often don't arise until after the disease has progressed to a more advanced stage, you should be having regular colon cancer screenings once you reach age 50—when the risk of colon cancer begins to increase markedly. Doctors estimate that up to 50% of all colon cancers could be prevented by regular screening.

Methods of screening include:

Digital rectal examination (yearly) as part of your annual physical exam.

Fecal occult blood test (yearly) - a laboratory test for tiny amounts of blood in your stool. While still not widely utilized, fecal occult tests that you can do at home are now available.

Flexible sigmoidoscopy (every five years) - an examination of the rectum and lower colon via the insertion of a thin tube with a light at the end of it.

Colonoscopy - strongly suggested every five years for patients with risk factors for colon cancer (especially a family history of colon or rectal cancer), and every 10 years for everyone else age 50 or older. This test, which uses a longer tube than the flexible sigmoidoscopy, allows for a more thorough examination of the entire colon, including removal and biopsy of a polyp found during the examination.

Virtual colonoscopy - a new test that is still in the experimental stage. It uses a CT scan to create a 3-dimensional image of the bowel that can be examined by a radiologist and a gastroenterologist. This method causes less discomfort than a regular colonoscopy but it doesn't allow for the removal and biopsy of polyps.

Treatment depends on when you start

If you have a colon exam that indicates the presence of polyps, a biopsy (removal of the polyp for examination) is done. If a polyp is found to be cancerous, surgery to remove the polyp(s) is usually performed and further treatment will depend mainly on what stage the cancer has progressed to. The stages of cancer refer to which tissues have been affected by the cancer.

• Early stage -
• The cancer is contained to the inner lining of the colon or the inside wall of the colon. Surgery is usually limited to removing the tissues found to be cancerous.
• Second stage
• The cancer has spread to the deeper layers of the colon or outside the colon to nearby tissue, but not to the lymph nodes. Surgery is performed to remove the cancerous part of the colon and a small amount of healthy tissue surrounding the cancerous cells. In addition, nearby lymph nodes are removed and tested to determine if the cancer has spread. Chemotherapy or radiation therapy may be recommended to kill any remaining cancer cells that may not have been removed by surgery.
• Third and fourth stages
• The cancer has spread beyond the colon and tissue near the colon to the lymph nodes and/or other parts of the body. Surgery is performed to remove cancerous parts of the colon and surrounding tissues. In addition, surgery to remove all or part of other organs to which the cancer has spread may be done. Radiation therapy and chemotherapy may also be utilized. Biological therapy—the use of drugs that cause the body itself to fight cancer cells—is available on an experimental basis only.

Prevention: what can you do?

The importance of regular screening tests for preventing colon cancer can not be emphasized enough. In addition, the following steps can help limit your risk for colon cancer:

• Eat a diet high in fruits and vegetables and low in animal fat.
• Limit your consumption of alcohol.
• Limit your consumption of meat, especially red meat. When eating red meat, choose cuts low in fat, slow cook the meat, and avoid eating meat, fish, and poultry that has been burned, charred, or heavily browned, as these cooking methods may contribute to the development of colon cancer.
• Exercise regularly and try to maintain a healthy weight.
• Don't smoke.
• Though a diet high in fiber has long been thought to protect against colon cancer, some recent studies have indicated otherwise. See: Food Fight about Fiber.

New research may aid prevention

In recent years, studies have uncovered a number of previously unknown factors related to colon cancer.

• Hereditary factors
• One study has led to the belief among most medical professionals that a large portion—up to an estimated 20%—of all colon cancer cases may be related to hereditary factors. Two such factors have been specifically identified: familial adenomatous polyposis and hereditary non-polyposis colon cancer (Lynch Syndrome). People with these two diseases are more likely than others to develop colon cancer. Another form of inherited colon cancer that effects only Jewish people of Eastern European descent has recently been discovered, although little else about it is known.
• Aspirin
• In addition to helping prevent heart attack and stroke, aspirin taken once daily may help to prevent the development of colon polyps, and thus, colon cancer. Studies are ongoing as to the best age to start taking aspirin.
• Vitamins and minerals
• One study has shown that regular intake of folic acid may greatly reduce the risk of developing colon cancer. Another study has shown that taking daily calcium supplements also may reduce your risk of developing colon cancer.
• Insulin resistance
• Finally, a recent study has shown that women who are insulin resistant—a condition that is often a precursor to diabetes—are at a much greater risk of developing colon cancer than women who are not insulin resistant.

Researchers are learning more and more about colon cancer, but since screenings can catch potential problems early on, why not just do it?