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About bowel cancer screening

Bowel cancer screening aims to find bowel cancer at an early stage in people with no symptoms. Early treatment is more likely to work. Bowel cancer screening can also find polyps. Polyps are not cancers, but may develop into cancers over time. They can easily be removed to reduce your risk of bowel cancer. 

Screening in the UK

There are separate bowel cancer screening programmes in England, Wales, Scotland and Northern Ireland. 

In England, people aged between 60 and 74 years old are invited for bowel screening every 2 years. A one-off bowel scope screening test is also being introduced. In Northern Ireland and Wales, men and women aged between 60 and 74 are offered bowel screening. In Scotland the programme covers people aged between 50 and 74. 

To get your screening invitations you need to be registered with a GP. Every 2 years, you get a testing kit through the post. It checks for hidden (occult) blood in your poo (stool or faeces). It is called an FOB test (faecal occult blood test). You do the test yourself at home. You smear a small sample of poo onto a piece of treated card. Then you send the card back in a hygienically sealed, prepaid envelope. You get the results through the post about 2 weeks later.

Only 2 out of every 100 people tested (2%) are likely to have a positive result, showing that there is bleeding somewhere in the bowel. This does not mean you have cancer. But it does mean you need further tests. Usually you have an examination of the inner lining of the bowel using a flexible tube with a light and camera on the end (a colonoscopy). Then a specialist can see inside your bowel and find out what is causing the bleeding.

Bowel scoping

Bowel scope screening uses a thin flexible tube with a tiny camera on the end to check the inside of the lower bowel. The test is also called flexible sigmoidoscopy. It is being introduced as part of the NHS bowel cancer screening programme in England. You have this test once, at the age of 55. Parts of Scotland are now trialling bowel scope screening in men and women aged around 60. You continue with FOB testing as above.

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What is bowel cancer screening

Cancer screening involves testing apparently healthy people for signs that could mean a cancer is developing.

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


Tests used in bowel screening

In the UK, bowel screening currently uses Faecal Occult Blood Testing, also called FOBT or FOB. This means looking for hidden traces of blood in poo (stool or faeces). There is also a test called Bowel scope, which is a thin tube with a camera at the end that looks inside the bowel.

Testing your poo for blood

Blood in your poo (stools or faeces) can be a sign of bowel cancer. You test for tiny traces of blood that you might not be able to see. You do the test in your own home, using a testing kit.

The kit is a simple way for you to collect small samples of your poo (bowel motions). You wipe the sample on a special card, which you then send 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 doesn't take long. You get the results of your test in the post within 2 weeks.

View a transcript of the video showing how to do the bowel cancer screening test.

Examining the bowel (Bowel scope)

Bowel scope screening uses a thin flexible tube with a tiny camera on the end to look at the inside of the large bowel. It is also called Flexi-Scope or flexible sigmoidoscopy screening (sometimes shortened to flexisig). This test looks for polyps, which are most likely to grow in the lower bowel. The polyps may develop into cancer if left to grow. It can also find cancers if they have already developed and is likely to pick them up at an early stage.

A specially trained nurse or doctor puts the tube into your back passage and looks at the lower part of the large bowel. The nurse or doctor gently pumps some carbon dioxide gas into the bowel to open it up so they can see more clearly. They usually remove any polyps they find straightaway, using a thin wire loop passed through the scoping tube.


Who has bowel cancer screening

There are separate bowel screening programmes in England, Wales, Scotland and Northern Ireland. The screening programmes send a bowel cancer testing kit (FOB testing) every 2 years to people eligible to take part. You need to be registered with a GP to get your screening invitations.

In England, men and women aged between 60 and 74 years old take part. People aged over 74 can request a screening kit by contacting the bowel cancer screening helpline on 0800 707 6060.

In England the screening programme is also starting to invite people for a bowel scope test to look at the inside of the lower bowel and rectum. You have this test once, at age 55. The FOB testing will continue at age 60.

Bowel screening programme impact statement

In Wales and Northern Ireland, bowel screening with a bowel testing kit (FOB testing) covers men and women between 60 and 74 years old.

Northern Ireland helpline: 0800 015 2514
Wales helpline: 0800 294 3370

In Scotland, bowel screening with a bowel testing kit covers people between 50 and 74 years old. If you're 75 or over, you can ask for a screening test by contacting the helpline on 0800 0121 833. Parts of Scotland are also trialling bowel scope screening in men and women aged around 60.


After bowel screening tests

You usually get the results of your tests 2 weeks later. Most people have a normal result. This doesn't completely rule out cancer. So, it is important to get to know your body and what is normal for you. See your GP if you have any unusual changes that don't go away.

Find out about the symptoms of bowel cancer.

An unclear result after an FOB test

Some people have an unclear result. This means there was a slight suggestion of blood in the sample. If this happens, the programme will send you another kit and ask you to do the test again. This is because the result could have been caused by other medical conditions. 

An abnormal result after an FOB test

Out of every 100 people who have the test, around 2 have an abnormal result. Other medical conditions or recent dental work can cause an abnormal FOB result and most people who have an abnormal result don't have cancer. You may also have an abnormal result if you eat a lot of red meat, turnips, or horseradish in the 3 days before the test. 

The screening programme may ask you to do the test again. Or you may have an appointment to see a specialist nurse at a bowel screening centre. The nurse will talk to you about having a test to look at the inside of your bowel. This is called a colonoscopy. 

Of those having a colonoscopy, around

  • half (50%) do not have cancer or polyps
  • 4 in 10 people (40%) have a polyp
  • 1 in 10 people (10%) have cancer

You can read our detailed information about colonoscopy.

After bowel scope screening

Out of every 300 people who have bowel scope screening, around 285 will have a normal result. This means that no polyps or cancers were found. Around 14 people will have polyps and may need to have further tests such as colonoscopy. Around 1 person has cancer. The screening centre will then let your GP know, who will refer you to a hospital specialist for treatment.


Benefits of bowel screening

If you have bowel cancer diagnosed at the earliest stage, there is a very good chance that the cancer can be cured. The statistics show that more than 9 out of 10 people (90%) survive their cancer for 5 years or more. When it is found at a late stage, the chances of survival are much lower. 

Bowel scope screening can reduce the risk of bowel cancer developing by finding 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 found during screening can usually be removed easily.

Research suggests that bowel cancer screening can lower the risk of dying from bowel cancer. The bowel cancer screening programme has only been fully up and running since 2010 so it is too early to say exactly how many lives it saves. But experts think that screening could save around 2,000 lives in the UK each year by 2025.

The Flexi-Scope trial was led by Cancer Research UK scientists. It showed that bowel scope screening helps to prevent bowel cancer. For every 300 people screened, it stops 2 from getting bowel cancer and saves 1 life from bowel cancer.

You can read about the research we are doing into cancer screening on our research into screening and early diagnosis page.


Risks of bowel screening

Bowel screening works well in finding cancer but it is not perfect. It doesn't always find cancer when it is there. So some people with bowel cancer will be missed. This is called a false negative result.

Some people will have a false positive result. It means that the tests pick something up even though they don't have bowel cancer. False positive results after FOBT can cause anxiety and lead to further investigations, such as colonoscopy. 

People having colonoscopy have a very small risk of serious bleeding from the bowel, or tearing the wall of the bowel.

Bowel scope screening is usually safe but in rare cases it can damage the bowel. About 1 person in every 3,000 may have serious bleeding. Sometimes the bowel can be torn but this is even rarer. If that happens, you need surgery straight away to repair the bowel. Most people recover fully.

There is a small chance that some people may be diagnosed and treated for bowel growths that would not have caused them any harm during their lives. This is called overdiagnosis.


Screening for people at higher risk

Bowel screening works well at reducing deaths from bowel cancer in people in their 50s, 60s and early 70s. As bowel cancer is rare in younger people, screening them is not useful. 

But some people can have regular screening at an earlier age, if they have certain conditions that increase their risk of bowel cancer. These include

  • Familial Adenomatous Polyposis (FAP)
  • Hereditary Non Polyposis Colorectal Cancer (HNPCC), also called Lynch syndrome
  • A strong family history of bowel cancer
  • Ulcerative colitis
  • Crohn's disease
  • Bowel polyps
  • A previous bowel cancer

You can read more about screening people at high risk of bowel cancer.


Related information

If you would like to find out more about genetic conditions that increase the risk of bowel cancer you can look at our page about inherited genes and specific cancers.

Our CancerStats section has detailed statistical information about bowel screening rates in the UK.

You can find details about the bowel screening programme in different languages on the NHS bowel screening programme website.

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Updated: 18 August 2015