Cancer Screening & PreventionJune 10, 2026·4 min read
By the CIRRUS Editorial Team — how we write and source this
Why colorectal cancer screening now starts at 45, not 50
Major guideline bodies lowered the recommended starting age — the epidemiological trend behind that decision is worth understanding.
Colorectal cancer incidence in adults under 50 has been rising for several consecutive decades even as overall colorectal cancer rates (driven by the older population, where most cases still occur) have declined thanks to screening and other factors — a trend significant enough that major guideline bodies, including the US Preventive Services Task Force, lowered the recommended average-risk screening start age from 50 to 45.
The cause of rising early-onset colorectal cancer isn't fully settled in the research — hypotheses under active study include dietary shifts, rising obesity rates, changes in gut microbiome composition, and reduced physical activity, but no single factor has been conclusively established as the primary driver, and it's likely a combination.
Screening options at 45 include the same choices available at older ages — colonoscopy, stool-based tests like FIT or multi-target stool DNA testing, or CT colonography — and the right choice depends on personal risk factors, family history, and preference, which is worth an explicit conversation with a primary care physician rather than assuming the guideline change means every 45-year-old needs the same test.
This article is general health information, not medical advice, and doesn’t replace evaluation by your own physician. Talk to a doctor about anything specific to your own diagnosis or treatment.