Colon Polyps

The following information comes from The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), a part of the National Institutes of Health (NIH) and the U.S. Department of Health and Human Services. To ensure that you're viewing the most up-to-date information, we recommend visiting the colon polyps entry at the NIDDK website.

On this page:

What are colon polyps?

A colon polyp is a growth on the surface of the colon, also called the large intestine. Sometimes, a person can have more than one colon polyp. Colon polyps can be raised or flat.

The large intestine is the long, hollow tube at the end of your digestive tract. The large intestine absorbs water from stool and changes it from a liquid to a solid. Stool is the waste that passes through the rectum and anus as a bowel movement.

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Are colon polyps cancerous?

Some colon polyps are benign, which means they are not cancer. But some types of polyps may already be cancer or can become cancer. Flat polyps can be smaller and harder to see and are more likely to be cancer than raised polyps. Polyps can usually be removed during colonoscopy — the test used to check for colon polyps.

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Who gets colon polyps?

Anyone can get colon polyps, but certain people are more likely to get them than others. You may have a greater chance of getting polyps if:

  • you're 50 years of age or older
  • you've had polyps before
  • someone in your family has had polyps
  • someone in your family has had cancer of the large intestine, also called colon cancer
  • you've had uterine or ovarian cancer before age 50

You may also be more likely to get colon polyps if you:

  • eat a lot of fatty foods
  • smoke
  • drink alcohol
  • don't exercise
  • weigh too much

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What are the symptoms of colon polyps?

Most people with colon polyps do not have symptoms. Often, people don't know they have one until the doctor finds it during a regular checkup or while testing for something else.

But some people do have symptoms, such as

  • bleeding from the anus. The anus is the opening at the end of the digestive tract where stool leaves the body. You might notice blood on your underwear or on toilet paper after you've had a bowel movement.
  • constipation or diarrhea that lasts more than a week.
  • blood in the stool. Blood can make stool look black, or it can show up as red streaks in the stool.

If you have any of these symptoms, see a doctor to find out what the problem is.

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How does the doctor test for colon polyps?

The doctor can use one or more tests to check for colon polyps.

  • Barium enema. The doctor puts a liquid called barium into your rectum before taking x rays of your large intestine. Barium makes your intestine look white in the pictures. Polyps are dark, so they're easy to see.
  • Sigmoidoscopy. With this test, the doctor puts a thin, flexible tube into your rectum. The tube is called a sigmoidoscope, and it has a light in it. The doctor uses the sigmoidoscope to look at the last third of your large intestine.
  • Colonoscopy. The doctor will give you medicine to sedate you during the colonoscopy. This test is like the sigmoidoscopy, but the doctor looks at the entire large intestine with a long, flexible tube with a camera that shows images on a TV screen. The tube has a tool that can remove polyps. The doctor usually removes polyps during colonoscopy.
  • Computerized tomography (CT) scan. With this test, also called virtual colonoscopy, the doctor puts a thin, flexible tube into your rectum. A machine using x rays and computers creates pictures of the large intestine that can be seen on a screen.

    The CT scan takes less time than a colonoscopy because polyps are not removed during the test. If the CT scan shows polyps, you will need a colonoscopy so they can be removed.
  • Stool test. The doctor will ask you to bring a stool sample in a special cup. The stool is tested in the laboratory for signs of cancer, such as DNA changes or blood.

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Who should get tested for colon polyps?

Talk with your doctor about getting tested for colon polyps if you're 50 years of age or older, or earlier if you have symptoms or someone in your family has had polyps or colon cancer.

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How are colon polyps treated?

In most cases, the doctor removes colon polyps during sigmoidoscopy or colonoscopy. The polyps are then tested for cancer.

If you've had colon polyps, the doctor will want you to get tested regularly in the future.

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How can I prevent colon polyps?

Doctors don't know of one sure way to prevent colon polyps. But you might be able to lower your risk of getting them if you:

  • eat more fruits and vegetables and less fatty food
  • don't smoke
  • avoid alcohol
  • exercise most days of the week
  • lose weight if you're overweight

Eating more calcium may also lower your risk of getting polyps. Some foods that are rich in calcium are milk, cheese, yogurt, and broccoli.

Taking a low dose of aspirin every day might help prevent polyps. Talk with your doctor before starting any medication.

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Points to Remember

  • A colon polyp is a growth on the surface of the colon, also called the large intestine.
  • Colon polyps can be raised or flat.
  • Some colon polyps are benign, which means they are not cancer.
  • Some types of polyps may already be cancer or can become cancer. Flat polyps can be smaller and harder to see and are more likely to be cancer than raised polyps.
  • Most people with colon polyps do not have symptoms.
  • Symptoms may include constipation or diarrhea for more than a week or blood on your underwear, on toilet paper, or in your stool.
  • Doctors remove most colon polyps and test them for cancer.
  • Talk with your doctor about getting tested for colon polyps if you're 50 years of age or older, or earlier if you have symptoms or someone in your family has had polyps or colon cancer.

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Hope through Research

The National Institute of Diabetes and Digestive and Kidney Diseases' Division of Digestive Diseases and Nutrition supports research into digestive conditions, including colon polyps. Researchers are studying why some people are more likely to get colon polyps than others. Researchers are also studying new tests and treatments to lower the risk of colon cancer in people with colon polyps.

Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research. For information about current studies, visit www.ClinicalTrials.gov.

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Pronunciation Guide

anus (AY-nuhss)
barium enema (BA-ree-uhm) (EN-uh-muh)
benign (bee-NYN)
colonoscopy (KOH-lon-OSS-kuh-pee)
computerized tomography scan (kom-PYOO-tur-eyezd) (toh-MOG-ruh-fee) (skan)
DNA (DEE-EN-AY)
intestine (in-TESS-tin)
polyp (POL-ip)
rectum (REK-tuhm)
sigmoidoscopy (SIG-moy-DOSS-kuh-pee)
stool test (stool) (test)
virtual (VUR-chuh-wuhl)

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For More Information

Fact sheets about other diagnostic tests are available from the National Digestive Diseases Information Clearinghouse at www.digestive.niddk.nih.gov.

National Digestive Diseases Information Clearinghouse
2 Information Way
Bethesda, MD 20892–3570
Phone: 1–800–891–5389
TTY: 1–866–569–1162
Fax: 703–738–4929
Email: nddic@info.niddk.nih.gov
Internet: www.digestive.niddk.nih.gov

The National Digestive Diseases Information Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health of the U.S. Department of Health and Human Services. Established in 1980, the Clearinghouse provides information about digestive diseases to people with digestive disorders and to their families, health care professionals, and the public. The NDDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government agencies to coordinate resources about digestive diseases.

This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired.

NIH Publication No. 09–4977
November 2008

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