Colon Polyps

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Colon Polyps

Topic Overview

Picture of the lower digestive system

What are colon polyps?

Colon polyps are growths in your large intestine (colon). The cause of most colon polyps is not known, but they are common in adults.

Most colon polyps are not cancer. But some growths can turn into colon cancer. If a colon polyp is the kind that can turn into cancer, it usually takes many years for that to happen.

People over 50 are more likely than younger people to get colon cancer. Experts recommend routine colon cancer testing for everyone age 50 and older who has a normal risk for colon cancer. People with a higher risk, such as African Americans and people with a strong family history of colon cancer, may need to be tested sooner. Talk to your doctor about when you should be tested. Finding and removing colon polyps can prevent colon cancer.

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 age 50 and older who has a normal risk for colon cancer. People with a higher risk, such as African Americans and people with a strong family history of colon cancer, may need to be tested sooner. The tests for colon cancer are:

  • Stool tests. In a fecal occult blood test (FOBT), a fecal immunochemical test (FIT), and a stool DNA test (sDNA), stool samples are checked for signs of cancer.
  • Colonoscopy. In this test, the doctor inserts a small viewing tube all the way into your colon and looks for polyps. The doctor can also take out any polyps he or she finds.
  • Flexible sigmoidoscopy. This test is like a colonoscopy, except that the viewing tube is shorter so the doctor can only look at the last part of your colon. Doctors can remove polyps during this test.
  • Computed tomographic colonography (CTC). This test is also called a virtual colonoscopy. A computer and X-rays make a detailed picture of the colon to help the doctor look for polyps.

Doctors often recommend colonoscopy because it lets them look at the whole colon and remove any polyps they find. If polyps are found during another type of test, you may still need colonoscopy so the doctor can remove the polyps.

What increases my 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.

Once 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.

Frequently Asked Questions

Learning about colon polyps:

Being diagnosed:

Getting treatment:

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  Colon Cancer: Which Screening Test Should I Have?

Symptoms

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 called a fecal occult blood test (FOBT).

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.

Exams 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.

Stool tests

  • Fecal occult blood test (FOBT). A fecal occult blood test (FOBT) is done to look for microscopic amounts of blood in stool. FOBT is a simple, low-cost screening tool for colon polyps or colon cancer. FOBT has been shown in studies to reduce the number of deaths from colon cancer. By itself, an FOBT is not evidence of colon polyps or colon cancer. And a negative FOBT (no blood found) does not mean that you do not have polyps or colorectal cancer. If a fecal occult blood test is positive for blood in the stool, it is important to have a colonoscopy to help your doctor find the source of the blood and remove polyps if they are found.
  • Fecal immunochemical test (FIT). This test also looks for blood in the stool, but it is more specific than the FOBT. There aren't as many restrictions on what you can eat before having this test, and fewer stool samples are required. If the test is positive for blood in the stool, you may need to have a colonoscopy.
  • Stool DNA test (sDNA). This test checks for changes to the cells in the colon by looking at DNA in the stool. Certain kinds of changes in cell DNA happen when you have cancer. Like the other stool tests, if your test is positive, you may need to have a colonoscopy.

Tests that look inside your body

  • Flexible sigmoidoscopy. Flexible sigmoidoscopy allows the doctor to look at the lower third of the colon. During a sigmoidoscopy exam, samples of any growths can be collected (biopsied). And precancerous and cancerous polyps can sometimes be removed.
  • Colonoscopy. This screening method lets a 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.
  • Computed tomographic colonography (CTC). This test is also called virtual colonoscopy. A computer and X-rays make a detailed picture of the colon to help the doctor look for polyps. If this test finds polyps, you may 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 age 50 and older who has a normal risk for colon cancer. People with a higher risk, such as African Americans and people 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 older than 50, screening may lower your risk of dying from colon cancer. Screening options include the following tests.

  • Stool tests, such as:
    • A fecal occult blood test (FOBT) every year.
    • A fecal immunochemical test (FIT) every year.
    • A stool DNA test (sDNA) every 5 years.
  • Flexible sigmoidoscopy every 5 years.
  • Stool test (FOBT or FIT) every year and a flexible sigmoidoscopy every 5 years.
  • Colonoscopy every 10 years.
  • Computed tomographic colonography (CTC), known as virtual colonoscopy, every 5 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.

Click here to view a Decision Point. Colon Cancer: Which Screening Test Should I Have?

People with a higher risk for colon cancer, such as African Americans and people 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 nonpolyposis 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.

The decisions about when to start and stop screening for colon cancer should be made with your doctor. These decisions will depend on how old you are, your family history, any health problems you may have, and the benefits you can expect from regular screening.

Follow-up testing

If a biopsy of polyps obtained during screening reveals only hyperplastic polyps of any size, routine follow-up screening is all that is needed. These polyps do not become cancerous.

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.

Treatment Overview

Most colon polyps do not cause any problems, but a sample of polyp tissue (called a biopsy) can be removed during screening if you have a flexible sigmoidoscopy or colonoscopy. The tissue is examined to find out if it is the kind of tissue that could become cancer.

Initial treatment

If adenomatous polyps are found during an exam 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 and need to be removed.

In some cases, very small polyps [5 mm (0.2 in.) or less] may not be removed. Some studies have concluded that even if they contain adenomatous tissue, these polyps take so many years to grow that they pose little risk of cancer, except in people who have inherited (familial) polyp syndromes.1

Most colon polyps are not likely to develop into cancer. 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.

Risks of removing polyps during colonoscopy

Complications from colonoscopy are rare. There is a slight risk of:

  • Puncturing the colon (less than 1 in 1,000) or causing severe bleeding by damaging the wall of the colon (less than 3 in 1,000).
  • Bleeding caused by removing a polyp.
  • Complications from sedatives given during the procedure.

Ongoing treatment

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.

Home Treatment

No home treatment is done for colon polyps. See the Treatment Overview section of this topic for more information.

But you can take action that may prevent colon polyps from developing:

  • Maintain a healthy body weight.
  • Quit smoking.
  • Use alcohol in moderation. Moderate alcohol use usually is defined as 1 alcoholic beverage a day for women and 2 for men.

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.

Other Places To Get Help

Organizations

American College of Gastroenterology
P.O. Box 342260
Bethesda, MD  20827-2260
Phone: (301) 263-9000
Web Address: www.acg.gi.org
 

The American College of Gastroenterology is an organization of digestive disease specialists. The Web site contains information about common gastrointestinal problems.


American Cancer Society (ACS)
Phone: 1-800-ACS-2345 (1-800-227-2345)
TDD: 1-866-228-4327 toll-free
Web Address: www.cancer.org
 

The American Cancer Society (ACS) conducts educational programs and offers many services to people with cancer and to their families. Staff at the toll-free numbers have information about services and activities in local areas and can provide referrals to local ACS divisions.


American Society of Colon and Rectal Surgeons
85 West Algonquin Road
Suite 550
Arlington Heights, IL  60005
Phone: (847) 290-9184
Fax: (847) 290-9203
Email: ascrs@fascrs.org
Web Address: www.fascrs.org
 

The American Society of Colon and Rectal Surgeons is the leading professional society representing more than 1,000 board-certified colon and rectal surgeons and other surgeons dedicated to treating people with diseases and disorders affecting the colon, rectum, and anus.


National Digestive Diseases Information Clearinghouse (NDDIC)
2 Information Way
Bethesda, MD  20892-3570
Phone: 1-800-891-5389
Fax: (703) 738-4929
Email: nddic@info.niddk.nih.gov
Web Address: www.digestive.niddk.nih.gov
 

This clearinghouse is a service of the U.S. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the U.S. National Institutes of Health. The clearinghouse answers questions; develops, reviews, and sends out publications; and coordinates information resources about digestive diseases. Publications produced by the clearinghouse are reviewed carefully for scientific accuracy, content, and readability.


References

Citations

  1. Itzkowitz SH, Potack J (2010). Colonic polyps and polyposis syndromes. In M Feldman et al., eds. Sleisenger and Fordtran’s Gastrointestinal and Liver Disease, 9th ed., vol. 2, pp. 2155—2189. Philadelphia: Saunders.

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.
  • Iqbal CW, et al. (2008). Surgical management and outcomes of 165 colonoscopic perforations from a single institution. Archives of Surgery, 143(7): 701–707.
  • Kastrinos F, Syngal S (2009). Colorectal cancer screening. In NJ Greenberger et al., eds., Current Diagnosis and Treatment: Gastroenterology, Hepatology, and Endoscopy, pp. 256–268. New York: McGraw-Hill.
  • Lanza E, et al. (2007). The Polyp Prevention Trial—Continued follow-up study: No effect of a low-fat, high-fiber, high-fruit, and -vegetable diet on adenoma recurrence eight years after randomization. Cancer Epidemiology, Biomarkers, and Prevention, 16(9): 1745–1752.
  • Levin B, et al. (2008). Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: A joint guideline from the American Cancer Society, the U.S. Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. CA: A Cancer Journal for Clinicians, 58(3): 130–160.
  • Rex DK, et al. (2009). American College of Gastroenterology guidelines for colorectal cancer screening 2008. American Journal of Gastroenterology, 104(3): 739–750.

Credits

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Jerome B. Simon, MD, FRCPC, FACP - Gastroenterology
Last Revised April 27, 2011

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