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About bowel cancer screening

Bowel cancer screening aims to detect 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 the risk of bowel cancer developing. 

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 69 years old are invited for bowel screening every 2 years. This is being extended to include people up to the age of 75. A one-off bowel scoping test to examine the inner lining of the lower part of the bowel is also being introduced for people aged 55. In Northern Ireland men and women aged between 60 and 71 are offered screening. They hope to extend the programme to include people up to the age of 74 from 2014. In Scotland the programme covers people aged between 50 and 74. In Wales, the screening programme invites people aged between 60 and 74 for screening. They aim to start screening from the age of 50 over the next few years.

To receive your invitations for screening you need to be registered with a GP. Every 2 years the screening programme sends you a testing kit through the post. This test checks for hidden (occult) blood in your stool (faeces). It is called an FOB test (faecal occult blood test). You can 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. Your results come by post too about 2 weeks later.

Only 2 out of every 100 people tested (2%) are likely to have a positive result, showing that there is blood in their stool. A positive FOB test 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 cameral on the end (a colonoscopy). Then a specialist can see inside your bowel and find out what is causing the bleeding.

Bowel scoping

In England, an extra one-off test is being introduced for people aged 55 as part of the NHS bowel cancer screening programme. The test is called bowel scoping or flexible sigmoidoscopy. It uses a flexible short tube to check the inside of the lower bowel. The FOB test will continue from age 60 as before.

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What is bowel cancer screening

Cancer screening involves testing apparently healthy people for signs that could indicate 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.


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 every 2 years to people eligible to take part. You need to be registered with a GP to receive your screening invitations.

In England, men and women aged between 60 and 69 years old take part. This is being extended to include people up to the age of 75. Currently, people aged 70 and over can request a screening kit by contacting the bowel cancer screening helpline on 0800 707 6060. 

In Northern Ireland, the programme covers men and women aged between 60 and 71. They hope to extend the programme to invite people up to the age of 74 from 2014.

In Scotland the programme screens people aged between 50 and 74 years. 

In Wales, the programme covers people aged between 60 and 74. They aim to start screening people from the age of 50 over the next few years.

In England the screening programme is also starting to invite people aged 55 for a one-off test to look at the inside of the lower bowel and rectum. This is called bowel scope screening. The FOBT testing will continue at age 60 as before.


Tests used in bowel screening

In the UK bowel screening currently uses Faecal Occult Blood Testing (also called FOBT or FOB for short). 

Testing your poo for blood

FOBT looks for hidden (occult) traces of blood in your poo (stools), which can be a sign of bowel cancer. You do this in your own home using a testing kit.

The testing kit is a simple way for you to collect small samples of your bowel motions. 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. A laboratory sends you the results of your test by post within 2 weeks.

Examining the bowel (Bowel scoping)

Bowel scoping 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-Scoping or flexible sigmoidoscopy screening (sometimes shortened to flexisig). 

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


After bowel screening tests

You usually receive the results of your tests 2 weeks later. Most people are told that the result shows no abnormality. 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 have any of them.

You can read our information about the symptoms of bowel cancer.

An unclear result after an FOBT test

Some people have an unclear result, which means there was a slight suggestion of blood in the sample. If this happens, the programme will send you another test kit and ask you 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.

An abnormal result after an FOBT test

In England, for every 1,000 people who have the test, around 20 (2%) will have an abnormal result. Other medical conditions or some things in your diet can cause an abnormal FOB result so this doesn't necessarily mean that you have cancer. You may be asked to do the test again or an appointment may be arranged for you to see a specialist nurse at a bowel screening centre. Around 16 of the 20 people will have an examination of the bowel called a colonoscopy to see whether there is a problem that needs treatment.

You can read our detailed information about colonoscopy.

Of the 16 people

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

After bowel scoping

Out of 300 people who have bowel scope screening, 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. If this occurs the screening centre will let your GP know who will refer you to a hospital specialist for treatment.


Benefits of bowel screening

When bowel cancer is found at the earliest stage, there is a very good chance of survival and more than 90% of people survive at least 5 years. When it is found late, the chances of survival are much lower. 

Bowel cancer screening tests 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 easily be removed.

Research has shown that screening with the current FOBT test reduces the chances of dying from bowel cancer by around 16% in men and women aged from 45 to 74. 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 it is predicted that the programme will save more than 2000 lives each year by 2025.

The Flexi-Scope trial led by Cancer Research UK scientists showed that this test 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.


Possible downsides of bowel screening

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

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

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

Bowel scope screening is usually safe but in rare cases it can cause harm to the bowel. About 1 person in every 3,000 may have serious bleeding caused by bowel scope screening. Sometimes the bowel can be torn but this is even rarer. You would need surgery straight away to repair the bowel. Most people recover fully.

There is a small chance of over diagnosis of precancerous changes with bowel screening. This means that some people may be diagnosed and treated for bowel growths that would not have gone on to cause them any harm during their lives.


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 are offered regular screening if they have certain conditions that raise their risk of developing bowel cancer. The conditions include

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

You can read more on the screening people at high risk of bowel cancer page.


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.

Bowel screening programme impact statement

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Updated: 12 November 2014