Bowel polyps

Bowel polyps are small growths on the inner lining of the large intestine (colon) or rectum. Bowel polyps are very common. They’re slightly more common in men than women and are most common in people over the age of 60.

Symptoms of bowel polyps

Bowel polyps don't usually cause any symptoms, so most people with polyps won't know they have them. They are often picked up during screening for bowel cancer.

However, some larger polyps can cause:

Bowel cancer risk

Polyps don't usually turn into cancer. But if some types of polyps (called adenomas) aren’t removed, there's a chance they may eventually become cancerous. Doctors believe that most bowel cancers develop from adenoma polyps.

Very few polyps will turn into cancer, and it takes many years for this to happen. Because of the risk of bowel polyps developing into cancer, your doctor will always recommend getting polyps treated.

Treatments for bowel polyps

There are several methods for treating polyps, but the most common procedure involves physically removing the polyp using a wire loop. This happens during a procedure called a colonoscopy.

The colonoscopy involves passing a flexible tube called a colonoscope through your bottom and up into your bowel. The colonoscope has a wire attached to it with an electric current through it.

This wire is used to:

  • burn off (cauterise) the polyp
  • cut off (snare) the polyp

Both of these methods are painless.

In rare cases, polyps may need to be treated by surgically removing part of the bowel.

This is usually only done when:

  • the polyp has some cell changes
  • it is particularly large
  • if there are a lot of polyps

After the polyp or polyps have been removed, they are sent to specialists in a laboratory, who will contact your consultant if:

  • the polyp has been completely removed
  • there is any risk of it regrowing
  • there is any cancerous change in the polyp

If there is a cancerous change in the polyp, you may need further treatment. Your specialist will be able to advise you on this.

Causes of bowel polyps

Doctors don't know the exact cause of bowel polyps. It is thought that they are caused by the body producing too many cells in the lining of the bowel. These extra cells then form into a bump, which is the polyp.

You may be more likely to develop bowel polyps if:

Diagnosing bowel polyps

Bowel polyps are usually found when your bowel is being looked at for another reason or during screening for bowel cancer.

If polyps are found, a colonoscopy or CT colonography is needed to view the whole of the large bowel and remove them at the same time.

Monitoring bowel polyps

Some people with a certain type of polyp may be at risk of it coming back in the future (recurring).

This is uncommon but means you'll need examining (by colonoscopy) at regular intervals of around three to five years. This is to catch any further polyps that may develop and potentially turn into bowel cancer.

The information on this page has been adapted from original content from the NHS website.

For further information see terms and conditions.

This page was published June 2018

This page is due for review January 2021

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