In short
The NHS sends a FIT (faecal immunochemical test) kit to people aged 50 to 74 every two years — 45 to 74 in Scotland. You collect a small poo sample at home and post it back. A positive result means hidden blood was found, not that you definitely have cancer.
Most bowel cancers develop from adenomatous polyps over many years. Removing polyps at colonoscopy is one of the most effective cancer-prevention steps available on the NHS.
People aged 75 and over can often self-refer to their local screening centre. High familial or genetic risk (including Lynch syndrome) is managed with extra surveillance, not only the two-year FIT.
How do you do the FIT test?
The kit arrives by post. You take a small sample of poo with the stick or bottle provided, seal it, and post it in the envelope. It takes a few minutes and does not need a hospital visit.
Complete it when it arrives even if you feel well. Screening is designed to find problems before symptoms.
What happens if the FIT test is positive?
A positive FIT means the test found tiny amounts of human blood. The next step is usually colonoscopy: a camera examination of the whole large bowel, often with sedation. Polyps can be removed during the same procedure and biopsies taken.
CT colonography (a CT ‘virtual colonoscopy’) is sometimes used if colonoscopy is not suitable. Flexible sigmoidoscopy looks only at the lower bowel.
Who needs extra bowel surveillance?
About 5% of bowel cancers are linked to inherited conditions. Lynch syndrome is the most common, caused by mismatch-repair gene changes. FAP causes hundreds of polyps and a very high lifetime risk if untreated.
A strong family history should be discussed with a GP. Those people are offered colonoscopic surveillance outside the standard FIT programme.
What are the key takeaways?
- FIT is a home poo test every two years from age 50–74 (45–74 in Scotland).
- A positive FIT is not a cancer diagnosis — it is a reason for colonoscopy.
- Most bowel cancers grow from polyps that can be removed before they turn malignant.
- Do the kit even if you feel well; see a GP for symptoms rather than waiting.
Care like this is out of reach for millions
The diagnosis, screening and treatment described here are routine in the UK. In Pakistan, Indonesia and Malaysia, poverty puts them out of reach — so a treatable cancer too often becomes a fatal one. World Aid Network funds treatment through locally-licensed oncologists for patients who cannot pay.
Frequently asked questions
Does a positive FIT mean I have cancer?
No. It means blood was detected. Colonoscopy finds the cause. Most people with a positive FIT do not have cancer.
I am 76 — can I still be screened?
People aged 75 and over can usually self-refer to their local NHS bowel screening centre. Ask your GP or the screening hub.
Is processed meat a cause of bowel cancer?
The WHO classifies processed meat as a Group 1 carcinogen for colorectal cancer. Limiting processed and red meat, eating fibre, keeping a healthy weight, exercising, not smoking and limiting alcohol all lower risk.
This guide is general information, not medical advice. It was reviewed by the World Aid Network editorial team for accuracy against NHS and World Health Organization sources. Always speak to a GP or qualified clinician about your own health.