Screening for people at high risk of bowel cancer

Screening test for people at high risk

People at high risk of bowel cancer have screening with a colonoscopy. Doctors sometimes call this a surveillance 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. 

Read more about having a colonoscopy

People at high risk of bowel cancer

A number of conditions can increase your risk of bowel cancer. These include:

An inherited bowel condition called familial adenomatous polyposis (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 regular colonoscopies if you have FAP. This is likely to be every 1-3 years, but talk to your team about how often you have the test.

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 used to be called HNPCC - hereditary non polyposis colorectal cancer. It is caused by an ​inherited​  change (mutation) in certain genes. This increases the risk of bowel cancer.

The British Society of Gastroenterology (BSG) advise that people with Lynch syndrome have a colonoscopy every 2 years.

They advise that:

• people with Lynch syndrome who have a change in the MLH1, MLH2 or EPCAM gene should be invited between the ages of 25 to 75

• people with Lynch syndrome who have a change in the MSH6 or PMS2 gene should be invited between the age of 35 and 75

In England, the NHS Bowel Cancer Screening programme now manages screening for people with Lynch syndrome. Every 2 years they invite people with Lynch syndrome to:

• see a specialist screening practitioner

• have a colonoscopy

Serrated polyposis syndrome (SPS) 

Serrated polyposis syndrome is when polyps occur in the bowel with jagged edges (serrated). It is sometimes called hyperplastic polyposis syndrome.

Research is looking into whether this is an inherited condition. 

If you have SPS you will be offered a colonoscopy every 1 to 2 years

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. 

Talk to your GP if you think you have a strong family history of bowel cancer. They can refer you to your local genetics clinic. 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 

Your ​gastroenterologist​ will let you know if they recommend regular colonoscopies and how often. This can depend on how stable your inflammatory bowel disease is at the time.

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 a colonoscopy at:

• 1 year after polyp removal

• 3 years after polyp removal

Some people might not have a follow up colonoscopy.