Colon polyps: Early intervention can prevent colon cancer

Colon polyps are tiny growths that form on the inside of the large intestine (also known as the colon). Polyps are very common and roughly one-third to one-half of all adults has them.

The presence of polyps in the colon or rectum often raises questions for patients and their family about the significance of finding a polyp, whether it means that one has or will develop colon or rectal (colorectal) cancer, or if the polyp will require surgery.

Some types of polyps (called adenomas) have the potential to become cancerous while others have almost no chance of becoming cancerous.

It is hence important to know that polyps are common (they occur in 30 to 50 per cent of adults), not all polyps will become cancer (and those that can turn cancerous take many years for them to become cancerous) and polyps can be completely and safely removed

The best course of action when a polyp is found depends on the number, type, size, and location of the polyp. People who have an adenoma removed will require a follow up examination, as new polyps may develop over time that need to be removed.

Polyps are very common in men and women of all races who live in industrialised countries, hence, dietary and environmental factors have been found to play a role in their development.

Although the exact causes are not completely understood, some lifestyle risk factors have been identified. People who mainly depend on a high fat diet, high in red meat or low fibre diet have an increased risk of developing colon polyps. Cigarette smoking and obesity is also associated with increased risk of developing these polyps.

Colon or rectal cancer is uncommon before the age 40. 90 per cent of cases occur after the age 50, with men somewhat more likely to develop polyps than women; therefore, colon cancer screening is usually recommended starting at age 50 for both sexes. It takes approximately 10 years for a small polyp to develop into cancer.

Polyps and colon cancer tend to run in families, suggesting that genetic factors are also important in their development. Any history of colon polyps or colon cancer in the family should be discussed with a healthcare provider, particularly if cancer developed at an early age (before the age of 60), in close relatives, or in multiple family members. As a general rule, screening for colon cancer begins at an earlier age (40) in people with a family history of colon cancer or polyps.

Polyps usually do not cause symptoms but may be detected during a colon cancer screening examination (such as flexible sigmoidoscopy or colonoscopy) or after a positive stool test. Polyps can also be detected on some special x-ray called barium enema, although small polyps are more difficult to see with x-ray.

Colonoscopy is the best way to evaluate the colon because it allows the doctor to see the entire lining of the colon and polyps seen during the procedure can be safely removed during this procedure. During colonoscopy, a doctor inserts a very thin flexible tube with a light source and small camera attached to it into the anus. The tube is advanced through the entire length of the large intestine (colon) so that he or she can visualise the entire lumen of the large intestines for any structural abnormalities such as polyps, or features of colon or rectal cancer.
Colonoscopy is also the best test for the follow-up examination of polyps. Virtual colonoscopy using CT technology is another test used to detect polyps in specific circumstances.

It is important to know that colon or rectal cancer is preventable if precancerous polyps are detected and removed before they become malignant (cancerous). Over time, small polyps can change their structure and become cancerous. Polyps are usually removed when they are found on colonoscopy, which eliminates the chance for that polyp to become cancerous.

Some lifestyle changes can reduce one’s chances of getting more polyps or suffering from colon cancer, such as; eating a diet that is low in fat but high in fruits, vegetables, and fibre. Losing weight, if one is overweight, and quitting or not smoking at all for non-smokers, and limiting the amount of alcohol one takes, can prevent polyp recurrences and development of colon cancer.

Dr. Ian Shyaka
Resident in Surgery, Rwanda Military Hospital,



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