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What are Polyps?

Colonic polyps are benign growths of the colon. They are defined as any visible collection of tissue extending into the colon. There are three major types of polyps. Hyperplastic polyps are

similar to skin tags. They tend to remain unchanged for years and are not pre-cancerous. Hamartomas are also not cancerous growths that are frequently present at birth. Adenomatous polyps show microscopic changes similar to cancer and are the most common type of polyps. Adenomatous polyps are rare before the age of 30.  They increase in frequency with age so by the age of 60, 60% of people will have one or more polyps. Polyps occur four times more frequently in men than in women.

  
Where are Polyps found?

Polyps can be found throughout the colon. However, polyps are more common in the lower part of the colon. Fifty percent of the polyps are found in the rectum and sigmoid. Only 10% are found in the right side of the colon.

Polyps and Colon Cancer

There is good evidence that adenomatous polyps can develop into cancer. Only 5% of all adenomatous polyps will develop into cancer. The larger the polyp, the more likely it is to develop into a cancer. Polyps smaller than 1 cm (3/8 inch) rarely develop into a cancer, polyps greater than 2 cm (3/4 inch) have a 30-50% risk of cancer. A small island of cancer cells can be found in benign polyps. Since cancer may develop in any size adenomatous polyps, all polyps should be removed.

What causes Polyps?

The majority of polyps do not cause any symptoms other than bleeding. Colonic polyps are unrelated to polyps in other parts of the body. While there is a family tendency to develop polyps, there is no known "cause" of polyps. Diet has no definite effect on the development or the prevention of polyps.

Do Polyps come back?

A person who has an adenomatous polyp has a high risk of developing additional polyps. Almost 20% of patients will have more than one polyp at the same time. Therefore, when a polyp is found, it is important to check the entire colon for additional polyps. Once removed, a polyp does not grow back; however, new polyps can develop. Over 30% of people with adenomatous polyps will develop new polyps within two years.

How are Polyps removed?

Polyps can be removed by colonoscopy. A colonoscope is a flexible tube containing fiber-optic light bundles. Usually performed as an outpatient, colonoscopy is very well tolerated. When a polyp is located, a wire loop is placed over it and tightened. The polyp is painlessly removed by cautery then retrieved and submitted for pathological (microscopic) examination. Surgery is rarely needed to remove a benign polyp. If cancer cells are located at the tip of the polyp, colonoscopy polypectomy will completely remove the risk of the cancer and surgery is usually not needed.

What can I do to help reduce the chance of Colon Polyps and cancer?

Since it is not really clear why colon polyps form in the first place, it is difficult to make suggestions as to what a person can do to decrease their risk of colon cancer. Certainly a healthy diet is always important. Many physicians have advocated the use of fiber supplements to reduce the risk of colon cancer in the past. Recent studies have shown that fiber supplementation may not reduce the risk of colon cancer. Other studies involving the use of calcium supplements (the equivalent of 1200 mg of calcium daily) have demonstrated a decreased risk of recurrence of colon polyps. Eating a diet including fresh vegetables and avoiding large amounts of meat and animal fat in the diet may have some effect on decreasing colon polyps. Some studies have suggested that regular bowel movements and avoiding constipation may also help to decrease the risk of recurrent polyp formation.

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