Screening for people at high risk of bowel cancer
This page tells you about screening for people at high risk of developing bowel cancer. You can find the following information
- A quick guide to what's on this page
- The UK bowel cancer screening programme
- People at high risk of bowel cancer
- An inherited bowel condition called FAP
- An inherited bowel condition called HNPCC (Lynch syndrome)
- A strong family history of bowel cancer
Who is screened for bowel cancer
The UK has a bowel cancer screening programme. The test checks for hidden blood in your poo (stool or faeces). This is called a faecal occult blood test (FOB test). People registered with a GP have a test every 2 years, between 60 and 74 years old. In Scotland, screening starts at 50.
In England, a test to examine the inside of the rectum and lower bowel, called flexible sigmoidoscopy or bowel scope, is gradually being introduced as part of the screening programme. You have this once at 55 years old. The FOB test will continue from 60 years old. Parts of Scotland are also trialling bowel scope screening in men and women aged around 60.
People in high risk groups for bowel cancer may have screening on the NHS at a younger age. This usually means having an examination of the whole of the inside of your bowel using a thin, flexible tube with a light and camera at the end. You can have early screening if you have
- An inherited condition called familial adenomatous polyposis (FAP) – also called familial multiple polyposis
- An inherited condition called hereditary non polyposis colorectal cancer (HNPCC) – also called Lynch syndrome
- Several relatives on one side of the family diagnosed with bowel cancer, or relatives diagnosed at a particularly young age (a strong family history)
- Ulcerative colitis or Crohn’s disease
- Had polyps removed from your bowel in the past
- Had bowel cancer before
You can view and print the quick guides for all the pages in the about bowel cancer section.
Bowel cancer screening in the UK aims to find bowel cancer at an early stage when treatment is most likely to work. It can also prevent bowel cancer in some people. Generally, bowel screening tests start between 50 and 60 years old, because bowel cancer is uncommon in people under 50.
You can read about the UK bowel cancer screening programme on the screening for bowel cancer page.
People with some conditions have a higher risk of getting bowel cancer at a younger age. They may have screening on the NHS earlier than in the bowel cancer screening programme. This usually means having a test called a colonoscopy to examine the whole of the inside of your bowel.
You can find out about colonoscopy.
The various conditions that can increase the risk of bowel cancer are listed on this page.
FAP stands for familial adenomatous polyposis (also called familial multiple polyposis). This is a rare disease that runs in families. It causes lots of polyps to grow in the bowel. There is a high risk that one of these polyps will become cancerous. So people with FAP are offered either colonoscopies or sigmoidoscopies every year, to check for cancerous polyps.
People with FAP are strongly advised by specialists to have surgery to remove their large bowel by the age of 25. This is because there is such a high probability of getting bowel cancer if you have FAP.
You can read more about familial adenomatous polyposis.
HNPCC stands for hereditary non polyposis colorectal cancer. It is also sometimes called Lynch syndrome. This is an inherited gene fault (mutation) that increases bowel cancer risk.
If you definitely have HNPCC, your specialist will suggest that you start screening either when you are 25, or 5 years before the age at which your youngest affected relative got bowel cancer. You are likely to have colonoscopies every 2 years. There is not enough evidence yet for specialists to advise having the large bowel removed to prevent bowel cancer in HNPCC. But your specialist may suggest this if you do get bowel cancer.
You can read more about hereditary non polyposis colorectal cancer.
This means that you have several relatives on the same side of your family diagnosed with bowel cancer, or diagnosed at a particularly young age.
If you have a strong family history, but no FAP gene or HNPCC gene, your specialist may advise you to have a colonoscopy when you are 35 to 45 years old. If you have no polyps, you probably won’t need another colonoscopy until you are 55. It takes many years for a polyp to develop into cancer, so more frequent colonoscopies are not necessary.
The more relatives you have with bowel cancer, or the younger the diagnosed relatives are, the higher the chance that there is a cancer gene in your family.
If you think you have a strong family history of bowel cancer, talk to your GP. They can refer you to your local genetics clinic. You will see someone who specialises in looking at family histories and working out the likely risk of a particular disease. They will ask about your family, and if necessary refer you to a bowel specialist for regular screening.
Ulcerative colitis and Crohn's disease are bowel diseases that cause inflammation and sores (ulceration) inside the bowel. You have an increased risk of bowel cancer if you have either of these diseases. 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 may have a screening colonoscopy 10 years after your symptoms first began. Your specialist may then suggest you have regular colonoscopies every 1 to 5 years, depending on your level of risk.
If you have had polyps removed from your bowel in the past, your doctor may suggest that you have a sigmoidoscopy or colonoscopy every so often. This is to pick up any more polyps before they develop into an invasive cancer.
How often you have a bowel examination depends on
- How many polyps you've had
- How big the polyps were
- How abnormal the cells in the polyps were
The larger the polyp and the more abnormal the cells, the greater the risk of cancer.
If you've had 1 or 2 polyps smaller than 1cm across, you have a slightly higher than average risk of bowel cancer, but it is still a very low risk. Your doctor may suggest you have a colonoscopy every 5 years. But if you then have a colonoscopy that finds no polyps at all, you may be able to stop this screening.
If you've had 3 or 4 polyps, or at least one that was more than 1cm across, you have a moderate (intermediate) risk of bowel cancer. Your specialist will probably suggest a colonoscopy every 3 years. But if you have 2 colonoscopies one after the other (consecutively) with no polyps at all, you may be able to stop this screening.
If you've had more than 5 polyps, or more than 3 that were bigger than 1cm across, you have a much higher than average risk of bowel cancer. Your specialist will advise you to have a colonoscopy every year until you stop having so many polyps. If you start to have fewer polyps at each colonoscopy, then you may be able to go down to screening every 3 years.
If you have had bowel cancer in the past, there is a risk that you could get another new bowel cancer. So your doctor may suggest that you have a sigmoidoscopy or a colonoscopy every few years.
If you are not at higher than average risk of bowel cancer, there is currently no screening available outside the age range covered by the UK bowel screening programmes.
If you have symptoms that could be caused by bowel cancer, you need to see your GP, who can refer you for tests if necessary.
If you are worried about bowel cancer, there are some things you can do which may reduce your risk of developing it. These include
- Eating a healthy, balanced diet that is high in fibre, fruit and vegetables, and low in red or processed meat
- Not smoking
- Keeping to a healthy weight
- Drinking less alcohol
- Being physically active – aim for 30 minutes of moderate activity at least 5 days a week
You might like to look at our information about reducing your risk of cancer.
Rated 4 out of 5 based on 44 votes
Question about cancer? Contact our information nurse team