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
- A strong family history of bowel cancer
Who is screened for bowel cancer
The UK has a bowel cancer screening programme. The screening test checks for hidden (occult) blood in your stool (faeces). This is called an FOB test (faecal occult blood test). People registered with a GP receive a test every 2 years, generally between the ages of 60 to 75. The screening age range varies slightly between England, Scotland, Wales and Northern Ireland. In Scotland, screening starts at age 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. This will be a one off test for everyone aged 55. The FOB test will continue from age 60 as before.
People in high risk groups for bowel cancer are offered screening on the NHS at a younger age than the bowel screening programme. This usually means having an examination of the whole of the inside of the bowel using a thin, flexible tube with a light and camera at the end. You can have 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)
- A strong family history of bowel cancer (several relatives on one side of the family diagnosed with bowel cancer, or relatives diagnosed at a particularly young age)
- 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 detect bowel cancer at an early stage when treatment is more likely to work. It can also prevent bowel cancer in some people. Generally, bowel screening tests start between the ages of 50 to 60 because bowel cancer is uncommon in people under the age of 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 are offered screening on the NHS earlier than in the bowel screening programme. This usually means having a test called a colonoscopy to examine the whole of the inside of the bowel.
You can find out about colonoscopy.
The various conditions that can increase the risk of bowel cancer are outlined 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 have 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 age 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. This is an inherited gene fault (mutation) that increases bowel cancer risk. But you don't have lots of polyps, as people with FAP do.
If you definitely have HNPCC, your specialist will suggest that you start screening at age 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 develop bowel cancer.
You can read more about hereditary non polyposis colorectal cancer.
A strong family history means that you have several relatives on the same side of the 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 the age of 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 the 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, where you will see someone who specialises in looking at family histories and working out the likely risk of a particular disease. They will ask you 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 ulceration inside the bowel. You have an increased risk of bowel cancer if you have either of these diseases.
The level of risk depends on different factors such as
- How long you have had the disease
- Which part of the bowel is affected
- How severe the disease 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 having regular colonoscopies every 1 to 5 years, depending on your 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 the following things
- How many polyps you've had
- How big the polyps were
- How abnormal the cells were
The larger the polyp and the more abnormal the cells, the greater the risk of developing cancer.
If you've had 1 or 2 polyps smaller than 1cm across, you have a slightly higher than average risk of developing bowel cancer, but it is still a very low risk. Your doctor may suggest 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 developing 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 developing 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 develop another primary 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 for people outside the age range covered by the UK bowel screening programmes.
If you have symptoms that could be due to bowel cancer you need to talk to 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 help to keep you healthy. These include
- Eating a healthy, balanced diet, for example, high in fresh fruit and vegetables and fish, and low in animal fats
- Being a non smoker
- Keeping a healthy weight
- Drinking less alcohol
- Taking notice of any new symptoms and reporting them to your doctor
You might like to look at our information about healthy living.
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