Patient information · Bowel cancer
What is my chance of getting bowel cancer?
Quick answer
Bowel cancer risk depends on age, family history, inherited conditions, previous polyps or bowel disease, and lifestyle factors such as smoking, weight, alcohol and diet.
Warning signs – bleeding, a lasting change in bowel habit, unexplained weight loss or anaemia – should always be checked, because early detection greatly improves outcomes.
Bowel cancer is one of the most common cancers in the UK, but it is also one of the most preventable and treatable when found early. Many people want a simple answer to the question “what is my chance?” The honest answer is that risk varies a great deal from person to person, and the most useful thing you can do is understand the factors that raise it and act on the warning signs.
See a doctor promptly if you have any of these
- Bleeding from the back passage or blood in your stool
- A persistent change in bowel habit (looser stools or going more often) lasting three weeks or more
- Unexplained weight loss or persistent tiredness
- A lump or persistent pain in your abdomen
- Iron-deficiency anaemia with no obvious cause
These symptoms are far more often caused by something harmless – but they should always be checked, because finding bowel cancer early dramatically improves the outcome.
What raises the risk of bowel cancer?
Things you cannot change
- Age – risk rises significantly with age, though bowel cancer can occur in younger adults too.
- Family history – having a close relative diagnosed, particularly at a young age, increases your risk.
- Inherited conditions – such as Lynch syndrome and familial adenomatous polyposis (FAP).
- Previous polyps or bowel disease – a history of adenomatous polyps, or long-standing inflammatory bowel disease (ulcerative colitis or Crohn's), raises risk.
Things you can influence
- Smoking and higher alcohol intake
- Being overweight, and low physical activity
- A diet high in processed and red meat and low in fibre
- Type 2 diabetes
Screening and early detection
The NHS Bowel Cancer Screening Programme uses the home FIT test and is being extended to invite people from the age of 50 in England (the rollout is phased, so check your current eligibility). Screening is designed for people without symptoms – if you have symptoms, you should be assessed directly rather than waiting for a screening invitation. For people with a strong family history, a bespoke screening plan – which may include earlier or more frequent colonoscopy – can be arranged.
Why a proper assessment beats an online calculator
Online risk calculators can be misleading because they cannot weigh up your symptoms, examination findings and family history together. A consultation allows your individual risk to be assessed accurately and, where appropriate, a FIT test or colonoscopy to be arranged quickly. Because polyps can be removed during colonoscopy before they ever become cancerous, assessment is not only about diagnosis – it is genuine prevention.
Frequently asked questions
At what age should I start thinking about bowel cancer risk?
Risk rises with age, and NHS screening is being extended to start at 50 in England. However, anyone with symptoms such as bleeding, a persistent change in bowel habit or unexplained anaemia should be assessed at any age, rather than waiting for a screening invitation.
Does a family history of bowel cancer mean I will get it?
No. A family history raises your risk but does not make bowel cancer inevitable. If you have a close relative affected, particularly at a young age, a tailored screening plan with earlier colonoscopy can be arranged.
Can bowel cancer be prevented?
Risk can be reduced through not smoking, keeping a healthy weight, staying active, moderating alcohol and eating more fibre. Removing polyps at colonoscopy also prevents many cancers from developing.
I have a positive FIT test but feel well – what next?
A positive FIT test should be followed by a colonoscopy. Feeling well does not rule out something that needs treating, and a positive result is an important signal to investigate.