Screening Can Save Your Life

Dear Dr. B: Are there any recommendations for colorectal cancer screening from the Canadian Task Force on Preventive Health Care? Yours, Mr.C.

Dear Mr. C: Yes. A statement from the Task Force on colorectal screening was published recently in the Canadian Medical Association Journal. These recommendations are for asymptomatic people with no personal history of ulcerative colitis, polyps or colorectal cancer. I will summarise the recommendations here:

Recommendations for people over the age of 50 who are at normal risk:

1. There is good evidence to suggest that these people should have annual or biennial (every two years) test to check for non-visible blood in the stool (fecal occult blood tests).

2. There is fair evidence to include flexible sigmoidoscopy (an office procedure). Some recommend this every five years.

3. There is insufficient evidence to recommend whether only one or both (1 and 2) should be performed.

4. There is insufficient evidence to include or exclude colonoscopy as an initial screening test in this age group. Some recommend colonoscopy every 10 years.

Recommendation for people at above-average risk:

1. There is fair evidence to include either genetic testing or flexible sigmoidoscopy of people in families with familial adenomatous polyposis – a condition in which multiple adenomatous polyps progressively develop throughout the colon. The polyps first appear after puberty. Other benign and malignant lesions may appear on the body.

2. There is fair evidence to include colonoscopy screening in the periodic health examination of people in families with hereditary non-polyposis colon cancer – a condition in which three family members are affected with colorectal cancer, two of whom are in successive generations and at least one is under the age of 45 years. It is unclear at what age the screening should start and how often colonoscopy should be done.

3. There is insufficient evidence to recommend colonoscopy for people who have a family history (people who have two or more first degree relatives) of colorectal polyps or cancer but who do not meet the criteria for hereditary non-polyposis colon cancer. Some experts recommend colonoscopy for this group as it is accepted that people with family history of colon and rectal cancer may be at increased risk but that this risk is not well defined.

What are the advantages of screening? To reduce the number of deaths from colorectal cancer.

What are the disadvantages? The incidence of false positive and false negative tests especially with fecal occult blood testing. There is incidence of perforation from flexible sigmoidoscopy (1.4 per 10,000 procedures) and colonoscopy (10 per 10,000 procedures).

Colorectal cancer is the third most common cancer in Canada. It accounts for more than 12 percent of cases of cancer in both sexes.

It was estimated that there would be 17,000 new cases and 6,500 deaths from colorectal cancer in Canada in 2000. These rates, especially among men, are among the highest in the world.

But how many of us are ready to submit ourselves to screening for colorectal cancer? Not many. The embarrassment and discomfort of a rectal examination, unpleasant bowel cleansing before flexible sigmoidoscopy and colonoscopy, risk of bowel perforation, and anxiety dissuade people from coming forward for screening. Even symptomatic patients take a long time before they see their doctors.

Well, Mr. C, if any of the recommendations apply to you then see your doctor and have yourself checked out. Prevention is better than…….?

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