Colon Polyps
Definition
Colon polyps are growths on the lining of the colon or rectum. The colon and the rectum are parts of the large intestine. It is all part of the digestive system.
The two most common kinds of polyp are:
- Adenomatous polyps—can become larger over time and may develop into cancer
- Hyperplastic polyps—do not increase in size and only rarely become cancerous
Colon Polyp

Causes
The cause of colon polyps is unknown. It may be partly due to hereditary factors. There is a genetic condition called polyposis coli. It causes thousands of adenomatous polyps throughout the bowel.
Risk Factors
Risk factors for colon polyps include:
- Age: over 50 years
- Family members with colon polyps or colon cancer
- History of colorectal cancer (or cancer of the large intestine)
- Obesity*¹
- High body mass index (in men) *²
Symptoms
Symptoms are often not present. Polyps are only found during an endoscopy or x-ray. If symptoms are present, they can include:
- Rectal bleeding
- Anemia
- Diarrhea , constipation , and/or bloating that lasts over a period of time
- Abdominal pain, rarely
Diagnosis
The doctor will ask about your symptoms and medical history. A physical exam will be done. Tests may include:
- Digital rectal exam—the doctor inserts a gloved finger into the rectum to feel for polyps.
- Stool test—a sample of your stool is checked for blood.
- Sigmoidoscopy —a thin, lighted, flexible tube is inserted into the rectum to examine the rectal area and the lower colon.
- Colonoscopy —a thin, lighted, flexible tube (longer than a flexible sigmoidoscopy tube) is inserted in the anus and used to view the entire colon.
- Barium enema and x-ray—a barium fluid is injected into the colon and rectum. Several x-rays are taken. The barium makes your colon show up on x-ray.
- Biopsy —a sample of tissue is removed for testing. It is sent to a lab to determine whether the polyp is adenomatous or hyperplastic. It will also be checked for cancer cells.
Treatment
Depending on the size of the polyp, it may be removed. Large polyps are at high risk for becoming cancerous. They should be removed. Usually, polyps can be removed by colonoscopy.
If the polyps are very large, you may need to have surgery to have them removed. Your doctor may send the tissue from the removed polyps to be tested for cancer.
Prevention
It’s not clear how polyps can be prevented. However, the following guidelines can help you stay healthy and may help prevent not only polyps but also colon cancer:
- Eat a high fiber diet with plenty of fruits, vegetables , and whole grains.
- Minimize the amount of animal fat in your diet. This occurs in beef and other meat products as well as full-fat dairy products.
- Exercise regularly.
- Maintain a healthy weight.
- Don't smoke.
- See your doctor for regular screenings after the age of 50.
- More frequent screenings may be needed if polyps are found.
RESOURCES:
American Society of Colon and Rectal Surgeons
http://www.fascrs.org/
National Institute of Diabetes and Digestive and Kidney Diseases
http://www.niddk.nih.gov/
CANADIAN RESOURCES:
Canadian Digestive Health Foundation
http://www.cdhf.ca/aboutcdhf.htm
The Canadian Association of Gastroenterology (CAG)
http://www.cag-acg.org/default.aspx
References:
American Society of Colon and Rectal Surgeons website. Available at: http://www.fascrs.org . Accessed October 11, 2005.
Beers MH, Berkow R. The Merck Manual of Diagnosis and Therapy . 17th ed. Hoboken, NJ: John Wiley & Sons; 1999.
Kasper DL, Braunwald E, Fauci AS, et al. Harrison's Principles of Internal Medicine . 16th ed. New York, NY: The McGraw-Hill Companies; 2005.
Mayo Foundation for Medical Education and Research website. Available at: http://www.mayo.edu/ . Accessed October 11, 2005.
What I need to know about colon polyps. National Digestive Diseases Information Clearinghouse website. Available at: http://digestive.niddk.nih.gov/ddiseases/pubs/colonpolyps_ez/ . Accessed October 11, 2005.
*¹2/5/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Kim Y, Kim Y, Lee S. An association between colonic adenoma and abdominal obesity: a cross-sectional study. BMC Gastroenterol. 2009;9:4.
*²5/11/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Jacobs ET, Ahnen DJ, Ashbeck EL, et al. Association between body mass index and colorectal neoplasia at follow-up colonoscopy: a pooling study. Am J Epidemiol. 2009;169:657-666.
Last reviewed January 2009 by Daus Mahnke, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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