About bowel cancer screening

Screening means looking for early signs of a disease in healthy people who do not have symptoms. Bowel cancer screening aims to detect bowel cancer at an early stage when treatment is more likely to work. 

Research has looked at 2 main ways of screening for bowel cancer

• Testing for blood in the stool (faeces)
• Examining the inside of the bowel

There is information about these tests further down this page.

UK bowel cancer screening programmes aim to detect bowel cancer at an early stage. Regular bowel screening has been shown to reduce the risk of dying from bowel cancer by 16%.

As well as finding cancer at an early stage, bowel cancer screening can find polyps on the inner lining of the bowel. Polyps develop when cells grow too quickly and form a clump known as a bowel polyp or an adenoma. These are usually benign (non cancerous) but some may contain cancer cells. They may develop into a cancer over a number of years. Polyps can easily be removed, which reduces the risk of bowel cancer developing.

There are separate bowel screening programmes in England, Wales, Scotland and Northern Ireland. In England and Northern Ireland, men and women aged between 60 and 69 years old are sent a stool testing kit (faecal occult blood test) every 2 years. People aged 70 and over can request a kit by contacting the bowel cancer screening helpline on 0800 707 6060. Soon, people aged 70 to 75 will also be routinely included.

The national bowel screening programme in Scotland screens men and women aged between 50 and 74 years. In Wales the screening programme is sending testing kits to people aged between 60 and 71, but aims to screen people between 50 and 74 by 2015.

Stool testing means looking for hidden (occult) blood in your stool (faeces). It is also called faecal occult blood testing, or FOB, for short.

If you are within the age range of the bowel cancer screening programme, you will get a testing kit through the post every 2 years. This is a simple way for you to collect small samples of your bowel motions. You do this in your own home. You wipe the sample on a special card, which you then send to a laboratory for testing in a hygienically sealed, prepaid envelope. There are detailed instructions with each kit. You may think that the test sounds a bit embarrassing or unpleasant, but collecting the samples only takes a  minute. You will be sent the results of your test by post within 2 weeks.

Only around 2 out of every 100 people tested (2%) are likely to have blood in their stool sample (an abnormal result). Other medical conditions or some things in your diet can cause an abnormal FOB result so this does not necessarily mean you have cancer. If you have an abnormal result, you will be offered an appointment with a specialist nurse at a bowel screening centre. You will have a more detailed examination, and may be offered a colonoscopy to see whether there is a problem that needs treatment.

In England, for every 1,000 people who have the FOB test, around 20 will have an abnormal result and may be asked to do the test again. Around 16 of those people will have a colonoscopy. Of those 16

• About 8 people will have nothing abnormal found at colonoscopy
• About 6 will have polyps
• About 2 will have cancer

Some people have an unclear result, which means there was a slight suggestion of blood in your FOB test sample. If you have an unclear result, you will be sent another FOB test kit and asked to do the test again. This is because the result could have been caused by medical conditions such as haemorrhoids (piles) or stomach ulcers. 

An abnormal result can happen if you eat a lot of red meat, turnips, or horseradish in the 3 days before the test. You can also have an abnormal result if you have had recent dental work that caused bleeding.

A normal test result doesn't completely rule out cancer. So, it is important to be aware of the symptoms of bowel cancer and see your GP if you are worried.

People who have an abnormal stool test (faecal occult blood test) as part of the NHS bowel cancer screening programme are offered a test called a colonoscopy. Colonoscopy involves a doctor or specialist nurse examining the inside of your bowel with a long flexible tube. You can read detailed information on the colonoscopy page. 

A large UK clinical trial looked into a new bowel screening test. The trial followed more than 170,000 people over 11 years to see who developed bowel cancer. More than 40,000 of those people between the ages of 55 to 64 had a test called flexible sigmoidoscopy. Flexible sigmoidoscopy is also called Flexi-Scope or Flexisig. It involves having a thin, bendy tube put a short way into the rectum and lower bowel. The tube has a tiny camera and light on the end, allowing the doctor to look at the inside wall of the bowel and remove any small growths or polyps.

The results of the study were reported in April 2010. The researchers found that the people who had screening with Flexi-Scope reduced their risk of bowel cancer by a third because any polys were removed at an early stage. Now in the UK, the Flexi-Scope test is being introduced into the bowel screening programme.

Some people are offered regular screening if they are thought to be at higher than average risk of bowel cancer. You can read more about this on the screening people at high risk of bowel cancer page.