A colorectal polyp is a growth that sticks out of the lining of the colon or rectum.
Intestinal polyps; Polyps - colorectal; Adenomatous polyps; Hyperplastic polyps; Villous adenomas
Causes, incidence, and risk factors
Polyps of the colon and rectum are usually benign. There may be single or many polyps, and they become more common as people age.
Over time, certain types of polyps, called adenomatous polyps, may develop into colon cancer. Another common type of polyp found in the colon is called a hyperplastic polyp, which usually does not develop into colon cancer.
Polyps bigger than 1 centimeter have a greater cancer risk than polyps under 1 centimeter. Risk factors include:
- Family history of colon cancer or polyps
- A type of polyp called villous adenoma
Polyps may also be associated with some inherited disorders, including:
- Familial adenomatous polyposis
- Gardner syndrome
- Juvenile polyposis
- Lynch syndrome (HNPCC)
- Peutz-Jeghers syndrome
There are usually no symptoms. However, the following symptoms may occur:
- Abdominal pain (rare)
- Bloody stools
- Fatigue associated with anemia
- Rectal bleeding
Signs and tests
A rectal examination may rarely reveal a polyp that can be felt by the health care provider. However, the physical exam is usually normal.
Tests that show polyps include:
Over time, adenomatous colorectal polyps can develop into cancer and should be removed. In most cases, the polyps may be removed at the same time a colonoscopy is performed. For patients with polyps, follow-up colonoscopy should be performed within 3 - 5 years to see if the polyps have returned.
Rarely, for polyps with a high potential of becoming cancerous, the health care provider may recommend a colectomy (removal of a part of the colon).
The outlook for patients with colorectal polyps is excellent, assuming the polyps are removed. Polyps that are left behind can develop into cancer over time.
Polyps can cause bleeding, and over time, can develop into cancers.
Calling your health care provider
Call your health care provider if you have
- Black, tar-like stools
- Blood during a bowel movement
- Change in bowel habits
The following is recommended to reduce the risk of developing polyps:
- Eat a diet low in fat and high in fruits, vegetables, and fiber
- Avoid smoking and excessive alcohol intake
- Maintain a normal body weight
Colonoscopy prevents colon cancer by removing polyps before they can become cancer. People over age 50 should have a colonoscopy screening, which makes earlier diagnosis and treatment possible. This may reduce the odds of developing colon cancer, or at least help catch it in its most treatable stage. Those with a family history of colon cancer or colon polyps may need to be screened at an earlier age.
See physical exam frequency for further recommendations about having a screening test.
Lieberman DA. Clinical practice: screening for colorectal cancer. N Engl J Med. 2009;361(12):1179-1187.
David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc., and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital.
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