Colon Polyps

Condition Overview

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. Over time, some polyps can turn into colorectal 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 colorectal cancer. If polyps get large, they can cause symptoms. You may have bleeding from your rectum or a change in your bowel habits.

How are they diagnosed?

Most polyps are found during tests for colorectal cancer. The tests for colorectal 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.

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.

What increases your risk?

You are more likely to have colon polyps if:

  • You are over 50.
  • Colon polyps or colorectal 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 colorectal cancer.

How are they are treated?

Doctors usually remove colon polyps, because some of them can turn into colorectal 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.

Symptoms

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 colorectal 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.

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.

Exams and Tests

How are they diagnosed?

Most colon polyps are found during tests for colorectal cancer. Unless the polyps are large and cause bleeding or pain, the only way to know if you have polyps is to have tests that explore the inside of your colon.

Several tests can be used to detect colon polyps. The tests may be used to screen for colon polyps and colorectal cancer. They can also be used 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 colon.

Stool tests

These tests include:

Fecal immunochemical test (FIT).

This test 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, you will need 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).

This test 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.

Stool DNA test (sDNA/Cologuard).

This test looks at DNA in the stool to see if there are changes in the cells of the colon. Certain kinds of changes in cell DNA happen when you have cancer. If your test is abnormal, 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. After you've had it, you and your doctor will know whether or not you have cancer.

Tests that look inside your colon

These tests include:

Flexible sigmoidoscopy.

It allows the doctor to look at the lower third of the colon. During a sigmoidoscopy exam, samples of any growths can be collected (biopsy). 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.

It lets the doctor inspect the entire colon for polyps and cancer. During the test, samples of any growths can be collected (biopsy). And precancerous and cancerous polyps usually can be removed.

CT colonography (virtual colonoscopy).

It 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.

Follow-up testing

If a biopsy of polyps found during screening shows only hyperplastic polyps of any size, routine follow-up screening is all that is needed. These polyps don't become cancerous.

Most doctors agree that if you've 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.

Who should be screened?

Your risk for colorectal cancer gets higher as you get older. Some experts say that adults should start regular screening at age 50 and stop at age 75. Others say to start before age 50 or continue after age 75. Talk with your doctor about your risk and when to start and stop screening.

How often you need screening depends on the type of test you get:

Stool tests.
Every 1 or 2 years for FIT or gFOBT.
Every 3 years for sDNA, also called FIT-DNA.
Tests that look inside the colon.
Every 5 or 10 years for sigmoidoscopy.
Every 5 years for CT colonography (virtual colonoscopy).
Every 10 years for colonoscopy.

Experts agree that people at higher risk may need to be tested sooner. This includes people who have a strong family history of colon cancer. Talk to your doctor about which test is best for you and when to be tested.

Treatment Overview

How are they treated?

Doctors usually remove colon polyps, because some of them can turn into colorectal cancer. Most polyps are removed during a colonoscopy. You may need to have surgery if you have a large polyp. The polyp is examined to find out if it is the kind that could become cancer.

After you have had polyps, you have a higher chance of developing new polyps.

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.

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 colorectal cancer because of a family history of colorectal 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.

Ongoing treatment

Regular screenings for colon polyps are the best way to prevent polyps from developing into colorectal 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.

Self-Care

How can you care for colon polyps?

Regular exams to look for colon polyps are the best way to prevent polyps from turning into colon cancer. These can include stool tests, sigmoidoscopy, colonoscopy, and CT colonography. Talk with your doctor about a testing schedule that is right for you.

To prevent polyps

There is no home treatment that can prevent colon polyps. But these steps may help lower your risk for cancer.

  • Stay active. Being active can help you get to and stay at a healthy weight. Try to exercise on most days of the week. Walking is a good choice.
  • Eat well. Choose a variety of vegetables, fruits, legumes (such as peas and beans), fish, poultry, and whole grains.
  • Do not smoke. If you need help quitting, talk to your doctor about stop-smoking programs and medicines. These can increase your chances of quitting for good.
  • If you drink alcohol, limit how much you drink. Limit alcohol to 2 drinks a day for men and 1 drink a day for women.

References

Citations

  1. 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.
  2. 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.

Credits

Current as of: April 29, 2020

Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD - Internal Medicine
Kathleen Romito MD - Family Medicine
Adam Husney MD - Family Medicine
Jerome B. Simon MD, FRCPC, FACP - Gastroenterology