Get the facts about colon cancer screening

As rites of passage go, having a colonoscopy when you turn 50 is a lot less fun than having your first legal glass of beer. But despite the inconvenience and discomfort, you'd be a fool to skip it. We'll give you the scoop on screenings and colorectal diseases.

• The risk of colon cancer begins to rise after you turn 40 but remains small until age 50, which is the point at which most medical groups recommend that all adults begin colon cancer screening.
• Your doctor may want you to start earlier and get checked more often if you're at high risk for the disease due to a personal or family history of colon cancer or polyps, or if you have chronic inflammatory bowel disease like ulcerative colitis or Crohn's disease.
• Many doctors continue to do fecal occult blood tests (FOBTs) based on stool samples obtained during a digital rectal exam. However, there is clear evidence that tests you perform yourself at home by obtaining samples from three consecutive bowel movements work better. Colorectal tumours bleed on and off, so a single sample may miss evidence of bleeding.
• One study found that the single-sample FOBT helped to detect just five percent of tumours. Not surprisingly, no major medical organization recommends this test.
•  A new version of the home test kit called the immunochemical fecal occult blood test may be more accurate than older tests and eliminate a key reason many people don't like performing the FOBT: having to avoid certain foods and medications for three days to a week before testing.
• In one study of 5,841 people, the immunochemical test detected 82 percent of existing colon tumours, while the older test identified only 64 percent. So which test is best for you? That's a question to discuss with your doctor. The answer may depend on what you're willing to do. The American Cancer Society recommends choosing one of the following five screening schedules:

1. A fecal occult blood test (FOBT) once a year.
2. A sigmoidoscopy every five years.
3. An FOBT plus sigmoidoscopy every five years (this combination is better than having either test alone).
4. A double-contrast barium enema every five years.
5. A colonoscopy every 10 years.

• If any of the first four tests is positive, you should have a follow-up colonoscopy. If a colonoscopy is negative, your doctor may decide there's no reason for further colon cancer screening of any kind for the next 10 years.

• If your doctor suggests a barium enema, say "no thanks" and opt for a different test instead.
• In a double-contrast barium enema (DCBE), a technician X-rays the intestines after they've been filled with barium and air through a tube inserted in the anus. But DCBE is far less sensitive than a colonoscopy and it may miss more than half of the large polyps in a colon.
• If you do have a DCBE and it detects signs of trouble, the American College of Gastroenterology recommends having a follow-up colonoscopy.

Colorectal cancer is a very common and extremely serious disease. It's the number two cause of cancer-related death in Canadian men and number three for women. Use this guide to learn the best detection methods and make sure that you stick to a reasonable test schedule. It could save your life.