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Colorectal polyps

Definition

A colorectal polyp is a growth that sticks out of the lining of the colon or rectum.

Alternative Names

Intestinal polyps; Polyps - colorectal; Adenomatous polyps; Hyperplastic polyps; Villous adenomas

Causes, incidence, and risk factors

Polyps of the colon and rectum are usually benign, meaning they are not cancer and they do not spread. There may be one 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:

• Age
• 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

Symptoms

There are usually no symptoms. However, the following symptoms may occur:

• Abdominal pain (rare)
• Blood in the stools
• Fatigue caused by losing blood over time

Signs and tests

A rectal examination may reveal a polyp if it is low enough in the bowel for the health care provider to feel. However, the physical exam is usually normal.

Most of the time, polyps are found when the following tests are done to screen for polyps and cancer:

• Barium enema
• Colonoscopy
• Sigmoidoscopy
• Stool test for hidden (occult) blood
• Virtual colonoscopy

Treatment

Because colorectal polyps can develop into cancer, they should be removed. In most cases, the polyps may be removed while a colonoscopy is being performed.

For patients with adenomatous polyps, new polyps can appear in the future. Follow-up colonoscopy is usually recommended 1 to 10 years later, depending on the:

• Patient's age and general health
• Number of polyps
• Size and characteristics of the polyps

Rarely, for polyps that are very likely to become cancerous, the health care provider may recommend a colectomy (removing part of the colon).

Support Groups

Expectations (prognosis)

The outlook for patients with colorectal polyps is excellent if the polyps are removed. Polyps that are left behind can develop into cancer over time.

Complications

Polyps can cause bleeding, and over time, can develop into cancers.

Calling your health care provider

Call your health care provider if you have

• Blood during a bowel movement
• Change in bowel habits

Prevention

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 consider having a colonoscopy or other screening test, 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.

References

Lieberman DA. Clinical practice: screening for colorectal cancer. N Engl J Med. 2009;361(12):1179-1187.

Burt RW, Barthel JS, Dunn KB, et al. NCCN clinical practice guidelines in oncology. Colorectal cancer screening. J Natl Compr Canc Netw. 2010;8:8-61.