A polyp is an abnormal growth on the inner surface of the large intestine, which includes the colon and the rectum. Sometimes a person can have more than one polyp. Colon polyps can be flat, but others are raised (as if they are on a stalk).
Polyps are one of the most common colorectal conditions, occurring in 15% to 20% of the adult population. Polyps can occur anywhere in the large intestine or rectum, but are more commonly found in the left colon, sigmoid colon, or rectum.
Some colon polyps are benign, which means they are not cancerous, but some can be precancerous or cancerous. The relationship of certain polyps to cancer is well established. Polyps can usually be removed during colonoscopy—the test used to check for colon polyps.
Anyone can get colon polyps, but certain people are more likely than others to get them. You may have a greater chance of getting polyps if:
Most people with colon polyps do not have symptoms. Often a doctor finds them during a regular checkup or while testing for something else.
Some people do have symptoms, such as:
Polyps are diagnosed by either looking at the colon lining directly (colonoscopy) or by a specialized CT scan called CT colography (also called a virtual colonoscopy). Barium enema x-rays have been used in the past and may be appropriate in some circumstances.
Talk with your doctor about getting tested if you are 50 or older. You may start screening tests at a younger age if you have symptoms or if someone in your family has had polyps or colon cancer.
Since there is no foolproof way of predicting whether or not a polyp is or will become cancerous, total removal of all polyps is advised. The vast majority of polyps can be removed by snaring them with a wire loop passed through the instrument. Small polyps can be destroyed simply by touching them with a coagulating electrical current. Most colon exams using the flexible colonoscope, including polyp removal, can be done on an outpatient basis with minimal discomfort. Large polyps may require more than one treatment for complete removal. Some polyps cannot be removed by instruments because of their size or position; surgery is then required. The polyps that are removed are taken to the lab and tested for cancer. If you have had colon polyps, the doctor will want you to be tested regularly in the future.
Doctors do not know of any sure way to prevent polyps, but you may be able to lower your risk by making healthier choices and changing poor habits.
If a polyp is removed completely, it is unusual for it to return in the same place. The same factors that caused it to grow in the first place, however, could cause polyp growth at another location in the colon or rectum. New polyps will develop in at least 30 percent of people who have previously had polyps.