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Screening for people at high risk of bowel cancer

People with some conditions have a higher risk of getting bowel cancer at a younger age than usual. They might have screening earlier than the normal NHS bowel cancer screening programme. 

Around 5 out of 100 (5%) bowel cancers are due to conditions passed on through families (inherited).

Screening aims to detect cancer at an early stage, when treatment is more likely to work. It can also help to prevent bowel cancer from developing in the first place. 

Screening test for people at high risk

People at high risk of bowel cancer have screening with colonoscopy. This test looks at the inside of the whole of the large bowel (colon). A specially trained healthcare professional (endoscopist) uses a flexible thin tube with a camera on the end to look at the bowel. 

People at high risk of bowel cancer

A number of conditions can increase your risk of bowel cancer.

An inherited bowel condition called familial adenomatous polyps (FAP) 

This is a rare condition that runs in families. It causes a lot of abnormal growths called polyps in the bowel. There is a high risk that one of these polyps will become cancerous. 

You have colonoscopies every year, if you have FAP. 

Specialists often advise people with FAP to have surgery to remove their large bowel (colon). This is because there is such a high risk of getting bowel cancer. 

An inherited bowel condition called Lynch syndrome 

Lynch syndrome is sometimes called HNPCC- hereditary non polyposis colorectal cancer. It is an inherited gene change (mutation) that increases your bowel cancer risk. 

You start screening when you are 25 if you have HNPCC. Or 5 years before the age of diagnosis of your youngest affected relative. You continue for every 12-24 months until you’re 75.  

A strong family history of bowel cancer 

This means you have several relatives on the same side of your family diagnosed with bowel cancer. Or you have a close relative diagnosed at a particularly young age. 

If you have a strong family history of bowel cancer, but no gene for FAP or Lynch syndrome, you might have a colonoscopy between the ages of 35 to 45. If you don't have any polyps, you won't need another colonoscopy until you are 55. 

Talk to your GP if you think you have a strong family history of bowel cancer. They can refer you to your local genetics clinc. You'll see someone who specialises in looking at family histories and working out the likely risk of a particular disease. They can refer you to a bowel specialist for regular screening if necessary. 

Ulcerative colitis or Crohn's disease 

Ulcerative colitis and Crohn's disease cause inflammation and sores (ulceration) inside the bowel. These diseases increase your risk of bowel cancer. 

Your level of risk depends on:

  • how long you have had the disease 
  • which part of your bowel is affected
  • how bad your colitis or Crohn's is 
  • whether you have a family history of bowel cancer 

You usually have a colonoscopy 10 years after the symptoms start. You might have colonoscopies every 1 to 5 years depending on your level of risk.

Polyps in the bowel 

Your doctor may suggest that you have regular tests to check the inside of your bowel, if you had polyps removed from the bowel in the past. This is to find any more polyps before they develop into cancer. 

How often you have these tests depends on:

  • how many polyps you've had 
  • how big the polyps were 
  • how abnormal the cells in the polyps were 

You might have tests every 1 to 5 years depending on your level of risk. 

Previous history of bowel cancer

There is a risk that you could get another new bowel cancer If you have had bowel cancer in the past.

You may have a colonoscopy every few years. 

If you are not in a high risk group 

There's no NHS screening available outside the age range covered by the UK bowel cancer screening programmes if you don't have a higher than average risk of bowel cancer.

Last reviewed: 
24 Aug 2018
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    C Cunnigham and others
    Colorectal disease, 2017. Volume 19, Pages 1-97

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    C Mowat, A Cole, A Windsor & others.
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