Colon Polyps

The term colon polyp describes a growth or mass that protrudes into the open space of the colon from the normal colon wall or lining. Colon polyps are a very common finding in men and women of all races, and some have the potential to become cancer. The transformation to cancer typically takes several years. Depending on location, type, and size, polyps can cause bleeding, anemia, abdominal pain, and obstruction, but are most commonly asymptomatic. This lack of symptoms is one reason screening tests such as colonoscopy are performed.

Risk factors for the development of colon polyps seem to include a high animal fat diet, especially red meat, low dietary fiber intake, obesity, and possibly cigarette smoking. Colon polyps are typically sporadic, but familial syndromes do exist leading to a predisposition for polyp and/or cancer development.

The most common types of polyps found in the colon are neoplastic or adenomatous, and nonneoplastic. There are several types of nonneoplastic polyps including hyperplastic, juvenile, inflammatory, and hamartomas. The most common type of nonneoplastic polyp is hyperplastic and these have historically been considered to have little or no potential to become malignant or cancerous. The adenomatous polyps, on the other hand, do have the potential to become malignant. Two-thirds of colon polyps are adenomatous, and most colon cancers come from adenomas. However, only a small percentage of adenomatous polyps develop into cancer. Larger adenomatous polyps are more likely to develop into cancer. Adenomas are further classified based on their microscopic (histological) appearance as tubular, villous (having a finger-like appearance), tubulovillous, pedunculated (having a stalk), or sessile (broad based).

Adenomatous polyps are growths arising from glandular tissue, compared to hyperplastic polyps that come from excessive proliferation or overgrowth of normal colonic tissue. The less common polyps include hamartomas, which arise from spontaneous new growth of otherwise normal tissue. Juvenile polyps are a type of hamartoma that are more likely to bleed. Inflammatory polyps are irregular and result from an inflammatory or immune response within the colon.

A procedure known as colonoscopy is usually how polyps are found. Colonoscopy procedures use a fiber optic camera inside the lumen of the colon to screen for colon cancer and are also performed for various other reasons. Generally, the polyps can be removed during colonoscopy, a procedure known as polypectomy. Some polyps are found to have malignant or cancerous characteristics upon further microscopic examination. Occasionally, very large polyps require a more aggressive surgical removal.

Once a person has been found to have colon polyps, they are at an increased risk to develop more. Research is ongoing to determine ways to prevent polyp formation. Some recommendations that have been made include avoiding cigarette smoking and heavy alcohol intake, and adding dietary calcium carbonate, folic acid, and selenium supplementation. Staying at your ideal body weight with a low-fat diet that is rich in fiber, fruits, and vegetables is also recommended.