What is Colon Polyp?
A polyp is a growth that occurs in the colon or other organs. These growths, or fleshy tumors, are shaped like mushrooms or dome-like buttons and occur on the inside lining of the colon. They may be as small as the tip of a pencil or as big as a golf ball. Colon polyps start out as benign growths, but over time they may become malignant. The larger the polyp the more likely it is to contain cancer. It is not clear why some people develop polyps and some do not. We do know that there is a hereditary component, and that the incidence increases with age. Some people believe there are dietary factors as well, but this has not been determined for sure.
While not every colon polyp turns into cancer, it is thought that every colon cancer starts out as a small non-cancerous polyp. It is important to remove these polyps while they are small. Fortunately, during colonoscopy these polyps are easily identified and removed, thus preventing colon cancer from developing.
There are several different kinds of colon polyps. Hyperplastic polyps are usually very small, often found in the rectum and are at very low risk for cancer. Pre-cancerous polyps (adenomatous or tubular adenoma) are the most common type of polyp found in the colon. Adenomatous polyps usually cause no symptoms, but if detected early can be removed before any cancer cells form. The larger the polyp, the higher the risk of it being pre-cancerous. A more serious type of pre-cancerous polyp is a villous adenoma or tubulovillous adenoma. These are less common and are often flatter and more difficult to remove. If dysplasia is present it means that abnormal cells (“almost cancer”) were seen under the microscope, and there is a greater risk of malignancy.
Detection of Colon Polyps
The key to the detection of colon polyps and the prevention of colon cancer is getting screened. Colon polyps will generally not produce any symptoms at all until the growth is quite large. To reduce your risk you must undergo periodic screening procedures even if you don’t have symptoms.
For individuals of average risk screening should begin at age 50. Individuals of high risk should start screening at a younger age. Factors that place you at higher risk are: a personal history of colon polyps or colon cancer, a family history of colon polyps or colon cancer, ulcerative or Crohn’s colitis or a personal history of breast or uterine cancer. There are also some hereditary conditions (familial polyposis and Lynch syndrome) that warrant very close surveillance.
The gold standard of screening tools is a colonoscopy. This procedure examines the entire colon with a flexible fiber-optic scope. The exam is usually done under sedation and is quite painless. Some of the other tests used to screen for polyps are a flexible sigmoidoscopy or a barium enema. However, these tests are not nearly as effective at detecting polyps and do not allow your doctor to remove any polyps during the exam. There has been a lot of discussion about “virtual colonoscopy” recently. Although this procedure may sound promising it has a long way to go. The drawbacks are that you will still need to do a bowel cleansing, which for many people is the worst part of the process. If polyps are visualized during the “virtual colonoscopy” you will need to schedule a standard colonoscopy to have the polyps removed; this will mean another bowel cleansing. During a “virtual colonoscopy” the technician will still be inflating your colon with air, which can cause cramping, and you will not be sedated for this procedure.
Treatment of Colon Polyps
Polyps can be removed during a colonoscopy by several different methods. If the polyp is small enough the doctor may just clip it off with a small forcep device. If the polyp is larger the doctor may remove it with a wire loop device (snare) and electro-cautery. Polyps can also be ablated (burned off) with laser like devices. Anytime a polyp is removed from your colon it will be sent to a pathologist for evaluation. This will determine if it is pre-cancerous or not, and will guide your physician in recommending a follow-up screening schedule.
Prevention of Colon Polyps
There is no guaranteed way to prevent polyps from forming. However, the risk of developing polyps can be lowered by taking a few small steps. Daily folic acid supplementation has been shown to reduce the incidence of recurrent polyps. Calcium supplements are also believed to be helpful, as is daily low-dose aspirin. And, although not proven, increasing your daily fiber intake is also thought to be helpful. Since none of these measures can reliably prevent the formation of polyps it is imperative that you follow the recommended screening guidelines for colonoscopy.