When should you start screening — and which test is right for you?
Average risk, family history, or symptoms: three different answers. A short decision guide.
Screening · 23 June 2026 · 5 min read · Dr. Ritesh Anand, MCh GI & Colorectal Surgeon
Screening means testing people without symptoms. If you already have symptoms, you are not screening — you are being investigated, and you should go straight to a diagnostic assessment.
Average risk, no symptoms
Most international guidelines now begin screening at 45. Options include a stool-based test (FIT) repeated annually, or a colonoscopy at longer intervals. FIT is easy and non-invasive; a positive FIT always needs a colonoscopy to follow.
Family history
- One first-degree relative with colorectal cancer or advanced polyps: typically start colonoscopy at 40, or ten years before their age at diagnosis — whichever is earlier.
- Two or more affected relatives, or any relative diagnosed very young: ask about genetic assessment for Lynch syndrome or familial polyposis.
- Personal history of inflammatory bowel disease: surveillance schedules are entirely different and are set by disease duration and extent.
The habits that change your baseline risk
Not glamorous, but consistently supported by evidence: stop smoking, keep alcohol low, reduce processed and red meat, increase fibre, stay physically active and manage weight. None of these replaces screening. Together, they meaningfully lower the odds you ever need the harder conversation.
If you are unsure which category you fall into, that itself is a good reason for one appointment. The interval you choose today decides how early the next thing gets found.
This article is general information, not a diagnosis. If your symptoms persist beyond three weeks, see a doctor in person rather than reasoning it out online.