Why screening works here
Most bowel cancers arise from a benign polyp that takes years to turn malignant. That window of time is what allows intervention beforehand: if the polyp is found and removed, the cancer never develops.
This is not just early detection. It is prevention in the strict sense.
Who needs it and when
- No family history or symptoms: population screening in Spain begins at 50 with a faecal occult blood test every two years
- One affected first-degree relative: it is worth starting earlier, usually ten years before the age at which that relative was diagnosed
- Several affected relatives or cases at a young age: individual assessment and sometimes genetic evaluation
- Previous polyps: the interval depends on the number, size and type, and ranges from one to ten years
- Long-standing ulcerative colitis or Crohn's colitis: a specific surveillance programme
If your stool test has come back positive
A positive result does not mean there is a cancer: in most cases a polyp or a benign cause is found. What it does mean is that a colonoscopy is needed, and that it should not be put off.
The tests, plainly
Faecal occult blood test. Simple, needs no preparation and very useful as a first filter in people without particular risk. If positive, colonoscopy follows.
Colonoscopy. The only test that allows the whole colon to be seen, biopsies taken and polyps removed in the same session. It is done under sedation and is not unpleasant.
CT colonography. An alternative in specific cases where colonoscopy is not possible, with the limitation that if it finds something, colonoscopy is needed anyway.
What happens if polyps are found
They are removed during the same colonoscopy and sent for analysis. The result determines when the test needs repeating. That interval is neither arbitrary nor the same for everyone: it depends on the number of polyps, their size and their characteristics under the microscope.
Leaving a colonoscopy without knowing when the next one is due is a loose end worth tying up at the results appointment.