Understanding Colon Polyps
What Is a Colon Polyp?
Polyps are benign growths (noncancerous tumors or neoplasms) involving the lining of the bowel. They can occur in several locations in the gastrointestinal tract but are most common in the colon. They vary in size from less than a quarter of an inch to several inches in diameter. They look like small bumps growing from the lining of the bowel and protruding into the lumen (bowel cavity). They sometimes grow on a “stalk” and look like mushrooms. Some polyps can also be flat. Many patients have several polyps scattered in different parts of the colon. Some polyps can contain small areas of cancer, although the vast majority of polyps do not.
How Common Are Colon Polyps? What Causes Them?
Polyps are very common in adults, who have an increased chance of acquiring them, especially as we get older. While quite rare in 20-year-olds, it’s estimated that the average 60-year-old without special risk factors for polyps has a 25 percent chance of having a polyp. We don’t know what causes polyps. Some experts believe a high-fat, low-fiber diet can be a predisposition to polyp formation. There may be a genetic risk to develop polyps as well.
What Are Known Risks for Developing Polyps?
The biggest risk factor for developing polyps is being older than 50. A family history of colon polyps or colon cancer increases the risk of polyps. Also, patients with a personal history of polyps or colon cancer are at risk of developing new polyps. In addition, there are some rare polyp or cancer syndromes that run in families and increase the risk of polyps occurring at younger ages.
Are There Different Types of Polyps?
There are two common types: hyperplastic polyp and adenoma. The hyperplastic polyp is not at risk for cancer. The adenoma, however, is thought to be the precursor (origin) for almost all colon cancers, although most adenomas never become cancers. Histology examination of tissue under a microscope) is the best way to differentiate between hyperplastic and adenomatous polyps. Although it’s impossible to tell which adenomatous polyps will become cancers, larger polyps are more likely to become cancers and some of the largest ones (those larger than 1 inch) can already contain small areas of cancer. Because your doctor cannot be certain of the tissue type by the polyp’s appearance, doctors generally recommend removing all polyps found during a colonoscopy.
How Are Polyps Found?
Most polyps cause no symptoms. Larger ones can cause blood in the stools, but even they are usually asymptomatic. Therefore, the best way to detect polyps is by screening individuals with no symptoms. Several other screening techniques are available: testing stool specimens for traces of blood, performing sigmoidoscopy to look into the lower third of the colon, or using a radiology test such as a barium enema or CT colonography. If one of these tests finds or suspects polyps, your doctor will generally recommend colonoscopy to remove them. Because colonoscopy is the most accurate way to detect polyps, many experts now recommend colonoscopy as a screening method so that any polyps found or suspected can be removed during the same procedure.
How Are Polyps Removed?
Most polyps found during colonoscopy can be completely removed during the procedure. Various removal techniques are available; most involve removing them with a wire-loop snare or biopsy forceps, with or without cauterization at the base of the polyp. Because the bowel’s lining is not sensitive, this is performed painlessly.
What Are the Risks of Polyp Removal?
Polyp removal (or polypectomy) during colonoscopy is a routine outpatient procedure. Possible complications, which are very uncommon, include bleeding from the polypectomy site and perforation (a hole or tear) of the colon. Bleeding from the polypectomy site can be immediate or delayed for several days; persistent bleeding can almost always be stopped by treatment during colonoscopy. Perforations rarely occur and may require surgery to repair.
How Often Do I Need Colonoscopy if I Have Polyps Removed?
Your doctor will decide when your next colonoscopy is necessary. The timing depends on several factors, including number and size of polyps removed, the polyps’ tissue type and the quality of the colon cleansing for your previous procedure. The quality of cleansing affects your doctor’s ability to see the surface of the colon. If the polyps were small and the entire colon was well seen during your colonoscopy, doctors generally recommend a repeat colonoscopy in 3-5 years. If your repeat colonoscopy doesn’t show any indication of polyps, you might not need another for 5 years. However, if the polyps were large and flat, your doctor might recommend an interval of only months before a repeat colonoscopy to assure complete polyp removal. Your doctor will discuss recommendations as your medical care is individualized to you.