Colonoscopy Screening Schedule
For average-risk adults, begin colonoscopy screening at age 45 years and repeat every 10 years, stopping at age 75 if prior screening was negative, or when life expectancy falls below 10 years. 1, 2
Starting Age for Average-Risk Individuals
Begin screening at age 45 years for average-risk adults, based on the most recent 2022 U.S. Multi-Society Task Force update that lowered the starting age from 50 to 45 years due to rising colorectal cancer incidence in younger adults. 1, 2
For those who have not initiated screening before age 50, screening should definitely begin at age 50 years at the latest. 1
The recommendation to start at age 45 reflects similar rates of advanced neoplasia in 45-49 year-olds compared to historical 50-year-old screening cohorts. 2
Screening Interval
Colonoscopy should be repeated every 10 years if the examination is high-quality (complete to cecum with adequate bowel preparation, performed by a colonoscopist with ≥25% adenoma detection rate) and shows no polyps or only small hyperplastic polyps. 1, 2
This 10-year interval is supported by research showing that individuals with normal baseline colonoscopy have an advanced neoplasm rate of only 3.4% at 10-year follow-up, comparable to initial screening populations. 3
Stopping Age
Stop screening at age 75 years for patients who are up-to-date with prior negative screening tests, particularly if they had a negative colonoscopy. 1, 2
Stop screening when life expectancy is less than 10 years, regardless of age, as the benefits no longer outweigh the harms. 1, 2
Discourage screening beyond age 85 years in all individuals, as harms clearly outweigh benefits at this age. 1, 2
For individuals without prior screening, consider screening up to age 85 depending on comorbidities and overall health status, though this is a weaker recommendation. 1
Modified Schedule for Family History
High-Risk Family History (First-degree relative with colorectal cancer or advanced adenoma diagnosed before age 60, OR two first-degree relatives at any age):
Begin colonoscopy at age 40 years OR 10 years before the youngest affected relative's diagnosis age, whichever comes first. 1, 4, 2
Repeat colonoscopy every 5 years (not every 10 years like average-risk). 1, 4, 2
Moderate-Risk Family History (Single first-degree relative diagnosed at age 60 or older):
Begin screening at age 40 years using average-risk screening options (colonoscopy every 10 years or annual FIT). 1, 4, 2
This population has modestly elevated risk (1.9 to 3-4 times higher than general population) but follows average-risk intervals starting earlier. 4
Quality Requirements for Colonoscopy
The colonoscopy must meet quality standards to justify the 10-year interval: cecal intubation rate >90%, withdrawal time ≥6 minutes, and adenoma detection rate ≥25% in men and ≥15% in women over 50. 1, 2
If quality standards are not met, the screening interval may need to be shortened. 1, 2
Post-Polypectomy Surveillance (Different from Screening)
If polyps are found, the schedule changes to surveillance (not screening):
1-2 small (<1 cm) tubular adenomas with low-grade dysplasia: Next colonoscopy in 5-10 years. 4
3-10 adenomas, OR any adenoma ≥1 cm, OR any villous features, OR high-grade dysplasia: Next colonoscopy in 3 years. 4
After a clear 3-year surveillance showing no polyps or only 1-2 small tubular adenomas, the interval can extend to 5 years. 4
Critical Caveats
African Americans may benefit from starting screening at age 45 years based on higher colorectal cancer incidence, though this is a weaker recommendation from older guidelines. 1
Symptomatic patients under age 50 with hematochezia, unexplained iron deficiency anemia, or melena should undergo colonoscopy regardless of screening age recommendations. 1
Incomplete colonoscopy or piecemeal polyp removal requires earlier follow-up (2-6 months) to verify complete examination or polyp removal before establishing the surveillance schedule. 4
Multiple relatives with polyps or cancer, especially before age 50, should prompt genetic counseling for Lynch syndrome or familial adenomatous polyposis, which require much more intensive surveillance (every 1-2 years for Lynch syndrome). 4, 2
Family history information is often incomplete or inaccurate; verify the diagnosis and age of onset in affected relatives when possible to ensure appropriate screening intensity. 4