The review synthesised 45 studies published between 2000 and March 2026 on population-based colorectal cancer screening performance, detection gaps and diagnostic delay in adults under 50. Detection of neoplasia and advanced adenomas was substantially higher at ages 45-49 than at younger ages, but a considerable proportion of early-onset cases occurred before 45 and thus outside current screening eligibility; younger adults presented with more advanced disease and longer diagnostic intervals.
Why it is interesting: It sets out how much of the rising early-onset colorectal burden sits below any plausible screening threshold, and how much of the remainder is a diagnostic-interval problem rather than a screening one.