Colorectal Cancer Prevention and Risk Management

Screening Tests

Screening tests are used to identify cancers very early, when the possibility of successful treatment is highest.

Most people should start being screened for colorectal cancer at age 50. However, if someone in your immediate family developed colorectal cancer before age 60 or if you have other significant risk factors, your doctor might recommend that you start being screened before you turn 50.

Doctors usually recommend an annual fecal occult blood test (FOBT) starting at age 50, a flexible sigmoidoscopy every 5 years, and a colonoscopy every 10 years.

Screening tests include:

• Colonoscopy - In this procedure, the doctor inserts a colonoscope, a long, flexible, lighted tube, through the rectum into the colon. The colonoscope allows your doctor to see the lining of the entire colon and possibly treat any problems. Your doctor might perform a biopsy to collect samples of suspicious tissues or cells so that they can be examined more closely. This procedure is usually done on an outpatient basis and requires anesthetic or heavy sedation.
• Digital rectal exam - The doctor inserts a lubricated and gloved finger into your rectum to feel for abnormal areas.
• Double-contrast barium enema - In this test, a chalky substance called barium is inserted through the rectum into the colon to coat and open the colon. The barium helps open the colon so that x-rays are clearer and more detailed. X-rays are taken of the colon and rectum, which the doctor evaluates for signs of polyps or other abnormal growths. This procedure is also known as a barium enema with air contrast.
• Fecal occult blood test (FOBT) - This test checks for hidden (occult) blood in the stool. Your doctor will ask you to place a very small amount of stool on a special card, which is then tested in the physician's office or sent to a laboratory.
• Flexible sigmoidoscopy - For this test, your doctor uses a lighted tube to look inside the rectum and the lower part of the colon (sigmoid colon) for polyps (bumps on the inside of the large intestine) or other possible signs of cancer. The physician might perform a biopsy to collect samples of suspicious tissues or cells so that they can be examined more closely. Flexible sigmoidoscopy is an outpatient procedure that does not require sedative anesthetic or pain medication. There are no or few complications associated with this procedure.

Most doctors recommend a colonoscopy if the FOBT is positive or if a sigmoidoscopy finds polyps (bumps inside the large intestine).

Prevention

Colorectal cancer is highly curable when it is detected early. When a polyp (bump inside the large intestine) develops in the colon or rectum, it takes 10 to 15 years to become cancerous. When doctors screen healthy people for colorectal cancer by colonoscopy or flexible sigmoidoscopy, they can find and remove polyps before they become cancerous.

Therefore, the best way to prevent colorectal cancer is to be screened regularly for this cancer. You should start being screened at age 50 if you have no known risk factors. Your doctor might advise you to start screening at a younger age if you have had colorectal cancer before, you have a close relative who has had the disease, or you have other known risk factors.

Research shows that the following steps might also be helpful in preventing colorectal cancer:

• Diet - Everyone should eat plenty of fruits, vegetables, and whole grain foods and limit the amount of high-fat food in the diet. However, it is not known if a diet low in fat and high in fiber decreases the risk of colorectal cancer. Some studies suggest that taking folic acid (also known as folate), calcium, magnesium, or vitamin D supplements can lower colorectal cancer risk.
• Exercise - The American Cancer Society recommends at least 30 minutes—or better yet, 45 to 60 minutes—of physical activity on 5 or more days of the week. If you are overweight, you should work with your doctor to find the right weight loss plan.
• Female hormones - Hormone replacement therapy (HRT) may reduce their risk of developing colorectal cancer in women who have gone through menopause. But women on HRT who do get colorectal cancer may have a fast-growing cancer.
• Nonsteroidal antiinflammatory drugs - Several studies have found that people who regularly take aspirin and other nonsteroidal antiinflammatory drugs (NSAIDs), such as Motrin or Advil (ibuprofen) or Aleve (naproxen), have a lower risk of colorectal cancer and adenomatous polyps (noncancerous growths in the colon and rectum that can become cancerous).

However, NSAIDs can cause serious or even life-threatening bleeding from stomach irritation. Therefore, experts do not recommend NSAIDs to prevent cancer for people at average risk of developing colorectal cancer. But these drugs might be useful for preventing colorectal cancer in people at increased risk of the disease. Research is currently looking into this issue.