A polyp is a fl eshy growth which can be found in many parts of the body. Unlike other polyps, a colorectal polyp is clinically important because it has the potential of becoming cancerous. Because colorectal cancer develops by progression from a benign polyp which is readily detectable and removable, it is one of the two human cancers which are easily preventable. The other is cervical cancer. Th e aphorism is, “if you don’t have a polyp you don’t get cancer, and if you have polyp and have it removed, you prevent cancer.”
Polyps possessing malignant potential are called adenomas and are present in 15% of the adult population. Fortunately not all of them turn malignant. What causes them to turn cancerous are the same factors causing cancer, namely, progessive genetic changes, ageing and an unhealthy lifestyle.
Most polyps have no symptoms at all and are not detected by the stool faecal occult blood test used in cancer screening. Th e best way to detect polyps is by colonoscopy which allows direct magnifi ed vision and importantly, enables removal and retrieval of the polyp.
It is recommended that an individual of either sex should have a colonoscopy by the age of 50, and repeat it every 10 years if normal. |
For an individual with first degree relatives (parents or siblings) with colorectal cancer or adenomas, the advice is to undergo a colonoscopy 10 years before the age of diagnosis of the relative and every fi ve years thereafter. In a small unique group of individuals with very bad familial cancer genes, colonoscopy is performed much earlier and more frequently.
It is now very clear that colonoscopy is eff ective in preventing cancer by removing
polyps, but it must be performed safely and carefully. Safely because of the danger of causing perforation of the colon which is a serious complication, and carefully because it is possible to miss polyps, especially in the right colon.
Recent data from the US shows that colonoscopy prevents 80% of left-sided cancer but only 40% from the right side. Th is is because the right colon is more difficult to reach. It also has more fl at polyps known as sessile serrated adenomas which are more difficult to detect and remove.
It is also recommended that each individual adopts a healthy lifestyle to reduce the risk of adenomas and cancer, and if possible and on your doctor’s advice, one should consider taking 100mg of Aspirin a day as it could reduce the incidence of polyps by 30%. |
