What are colon polyps?
Over time, some polyps can turn into colon cancer. It usually takes many years for that to happen.
What are the symptoms?
You can have colon polyps and not know it, because they usually don't cause symptoms. They are usually found during routine screening tests for colon cancer. A screening test looks for signs of a disease when there are no symptoms.
If polyps get large, they can cause symptoms. You may have bleeding from your rectum or a change in your bowel habits. A change in bowel habits includes diarrhea, constipation, going to the bathroom more often or less often than usual, or a change in the way your stool looks.
How are colon polyps diagnosed?
Most polyps are found during tests for colon cancer. Experts recommend routine colon cancer testing for everyone between the ages of 50 and 74 who has a normal risk for colon cancer. People with a higher risk, such as those with a strong family history of colon cancer, may need to be tested sooner. The tests for colon cancer include stool tests that can be done at home and procedures, such as a colonoscopy, that are done at your doctor's office or clinic.
What increases your risk of getting colon polyps?
You are more likely to have colon polyps if:
- You are over 50.
- Colon polyps or colon cancer runs in your family.
- You inherited a certain gene that causes you to develop polyps. People with this gene are much more likely than others to get the kind of polyps that turn into colon cancer.
How are they treated?
Doctors usually remove colon polyps, because some of them can turn into colon cancer. Most polyps are removed during a colonoscopy. You may need to have surgery if you have a large polyp.
After you have had polyps, you have a higher chance of developing new polyps. If you have had polyps removed, it is important to have follow-up testing to look for more polyps. Talk to your doctor about how often you need to be tested.
Colon polyps usually do not cause symptoms unless they are larger than 1 cm (0.4 in.) or they are cancerous. The most common symptom is rectal bleeding. Sometimes the bleeding may not be obvious (occult) and may only be discovered after doing a screening test for blood in the stool.
Colon polyps usually do not cause pain or a change in bowel habits unless they are large and are blocking part of the colon. These symptoms are rare, because polyps usually are discovered and removed before they become large enough to cause problems.
After cancer develops, additional symptoms may occur, such as changes in bowel habits and significant weight loss.
Examinations and Tests
Unless colon polyps are large and cause bleeding or pain, the only way to know if you have polyps is to have one or more tests that explore the inside surface of your colon.
Several tests can be used to detect colon polyps. Two of these exams, flexible sigmoidoscopy and colonoscopy, also can be used to collect tissue samples (called a biopsy) or to remove colon polyps. All the tests may be used to screen for colon polyps and colon cancer and as follow-up tests after colon polyps have been removed. There are two basic types of tests—stool tests and tests that look inside your body.
- Fecal immunochemical test (FIT) is done to look for microscopic amounts of blood in the stool. There aren't any restrictions on what you can eat before having this test. If the test is positive for blood in the stool, it is important to have a colonoscopy. This will help your doctor find the source of the blood and remove polyps if they are found.
- Fecal occult blood test (FOBT) also looks for blood in the stool, but it isn't as specific as the FIT. There are restrictions on what you can eat before having this test. If this test is positive for blood in the stool, you will need to have a colonoscopy.
An abnormal result from a stool test doesn't mean that you have colorectal cancer. It might be a false-positive result. So the next step is to have a colonoscopy. Once you've had the colonoscopy, you and your doctor will know whether or not you have cancer.
Tests that look inside your body
- Flexible sigmoidoscopy allows the doctor to look at the lower third of the colon. During a sigmoidoscopy examination, samples of any growths can be collected (biopsied). And precancerous and cancerous polyps can sometimes be removed. But if your doctor finds polyps, you will need to have a colonoscopy to check the upper part of your colon.
- Colonoscopy lets the doctor inspect the entire colon for polyps and cancer. During a colonoscopy, samples of any growths can be collected (biopsied). And precancerous and cancerous polyps usually can be removed.
- CT colonography (virtual colonoscopy) uses X-rays to make a detailed picture of the colon to help the doctor look for polyps. If this test finds polyps, you will need to have a colonoscopy.
Screening for colon cancer
Screening for colon cancer with a single test or a combination of tests reduces your chance of having complications and dying from colon cancer. Experts recommend routine colon cancer testing for everyone between the ages of 50 and 74 who has a normal risk for colon cancer. People with a higher risk, such as those with a strong family history of colon cancer, may need to be tested sooner. Talk to your doctor about when you should be tested.
If you are between the ages of 50 and 74, screening may lower your risk of dying from colon cancer. Screening options include the following tests.
- Stool tests every 1 to 2 years, such as:
- A fecal immunochemical test (FIT)
- A fecal occult blood test (FOBT)
- Flexible sigmoidoscopy every 5 years
- Colonoscopy every 10 years
The method of screening that you have depends on your personal preferences, your doctor's preferences, and what the clinic or office you go to is able to do.
People with a higher risk for colon cancer, such as those with a strong family history of colon cancer, may need to be tested sooner. Talk to your doctor about when you should be tested.
If you have a family history of familial adenomatous polyposis (FAP), you should start screening tests at age 10 or 12.
If you have a family history of hereditary non-polyposis colon cancer (HNPCC), you should have a colonoscopy every 1 to 2 years starting at age 20 to 25, or 10 years younger than the age at which the youngest family member who has colorectal cancer was diagnosed, whichever comes first.
Talk with your doctor. Decide with him or her when to start and stop screening for colon cancer. These decisions will depend on how old you are, your family history, any health problems you have, and the benefits you can expect from regular screening.
Most doctors agree that if you have had one or more adenomatous polyps removed, you probably need regular follow-up colonoscopy exams every few years. This type of polyp is more likely to turn into cancer, but that risk is still very low. How often you need a colonoscopy may depend on the number and size of the polyps, your age, your health, and other risk factors that you may have for polyps. Talk with your doctor about the follow-up testing schedule that is right for you.
Polyps are removed during screening if you have a colonoscopy. The polyp is examined to find out if it is the kind that could become cancer.
If adenomatous polyps are found during an examination with flexible sigmoidoscopy, a colonoscopy will be done to look for and remove any polyps in the rest of the colon.
The bigger a colon polyp is, especially if it is larger than 1 cm (0.4 in.), the more likely it is that the polyp will be adenomatous or contain cancer cells.
If only hyperplastic polyps are found during your flexible sigmoidoscopy, you likely do not need to have a colonoscopy. These polyps do not become cancerous. In this case you can continue your regular screenings, unless you are at an increased risk for colon cancer because of a family history of colon cancer or an inherited polyp syndrome.
A sessile polyp doesn't have a stalk. It is mostly a flat growth. Like other colon polyps, it grows on the inside wall of the colon. Sessile polyps can turn into cancer. Like other polyps, they are removed if found during sigmoidoscopy or colonoscopy.
Risks of removing polyps during colonoscopy
Complications from colonoscopy are rare. There is a slight risk of:
- Puncturing the colon or causing severe bleeding by damaging the wall of the colon. (This happens in less than 3 out of 1,000 people having a colonoscopy.footnote 1, footnote 2)
- Bleeding caused by removing a polyp.
- Complications from sedatives given during the procedure.
Regular screenings for colon polyps are the best way to prevent polyps from developing into colon cancer.
Most colon polyps can be identified and removed during a colonoscopy.
If you have had one or more adenomatous polyps removed, you probably need regular follow-up colonoscopy exams every 3 to 5 years. Talk with your doctor about the follow-up schedule that he or she thinks is best for you.
Treatment if the condition gets worse
Surgery is sometimes needed for large colon polyps that have a broad area of attachment (sessile polyps) to the colon wall. These large polyps sometimes cannot be removed safely during a colonoscopy and may be more likely to develop into cancer.
If cancer is found when the colon polyps are examined, you will begin treatment for colorectal cancer. For more information, see the topic Colorectal Cancer.
No home treatment is done for colon polyps. See Treatment Overview for more information.
But you can take action that may prevent colon polyps:
- Stay at a healthy body weight.
- Quit smoking.
- Limit how much alcohol you drink.
Experts are not yet certain that these approaches prevent colon polyps or colorectal cancer.
These self-care methods should not be a substitute for regular colorectal screening, especially if you are older than 50 or are at increased risk for colon polyps or colon cancer. While these approaches may decrease your risk for colon polyps, they will not prevent you from ever having colon polyps.
- Warren JL, et al. (2009). Adverse events after outpatient colonoscopy in the Medicare population. Annals of Internal Medicine, 150(12): 849–857. DOI: 10.7326/0003-4819-150-12-200906160-00008. Accessed February 2, 2015.
- Rabeneck L, et al. (2008). Bleeding and perforation after outpatient colonoscopy and their risk factors in usual clinical practice. Gastroenterology, 135(6): 1899–1906. DOI 10.1053/j.gastro.2008.08.058. Accessed February 13, 2015.
Other Works Consulted
- Bresalier RS (2010). Colorectal cancer. In M Feldman et al., eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 9th ed., vol. 2, pp. 2191–2238. Philadelphia: Saunders.
- Lieberman DA, et al. (2012). Guidelines for colonoscopy surveillance after screening and polypectomy: A consensus update by the U.S. Multi-Society Task Force on Colorectal Cancer. Gastroenterology, 143(3): 844–857.
- Rex DK, et al. (2009). American College of Gastroenterology guidelines for colorectal cancer screening 2008. American Journal of Gastroenterology, 104(3): 739–750.
- Syngal S, Katrinos F (2012). Colorectal cancer screening. In NJ Greenberger et al., eds., Current Diagnosis and Therapy: Gastroenterology, Hepatology, and Endoscopy, 2nd ed., pp. 273–286. New York: McGraw-Hill.
- U.S. Preventive Services Task Force (2008). Screening for colorectal cancer: U.S. Preventive Services Task Force recommendation statement. Available online: http://www.uspreventiveservicestaskforce.org/uspstf/uspscolo.htm.
Adaptation Date: 2/20/2019
Adapted By: HealthLink BC
Adaptation Reviewed By: HealthLink BC
Adaptation Date: 2/20/2019
Adapted By: HealthLink BC
Adaptation Reviewed By: HealthLink BC