Colonoscopy Screening Guidelines for Average-Risk Adults
Begin colorectal cancer screening at age 45 years with colonoscopy every 10 years or annual fecal immunochemical test (FIT) as first-tier options for average-risk adults. 1, 2
When to Start Screening
Start at age 45 years for all average-risk adults, which represents a qualified recommendation based on rising colorectal cancer incidence in younger adults (51% increase from 1994-2014 in those under 55 years). 1
The recommendation for screening at age 50 years and older remains a strong recommendation with more robust evidence. 1
African Americans should begin screening at age 45 due to higher colorectal cancer risk and mortality rates. 1, 3
Screening Test Options
First-Tier Tests (Strongest Evidence)
Colonoscopy every 10 years - preferred option that uniquely detects AND removes precancerous polyps during the same procedure, providing 10 years of protection after a negative result. 1, 2, 3
Annual FIT (fecal immunochemical test) - preferred stool-based option with proven mortality reduction. 1, 2, 3
Second-Tier Tests (Acceptable Alternatives)
Multitarget stool DNA test (FIT-DNA/Cologuard) every 3 years - has 87% specificity with 13-40% false-positive rates requiring follow-up colonoscopy. 1, 3
CT colonography every 5 years. 1
Flexible sigmoidoscopy every 5 years. 1
Tests NOT Recommended
Do not use blood-based tests (including Septin9 serum assay) - lack evidence for mortality benefit and are not guideline-endorsed. 4, 5, 6
Do not use capsule endoscopy, urine tests, or serum screening tests for average-risk screening. 5
When to Stop Screening
Stop at age 75 years for patients up-to-date with prior negative screening tests, particularly colonoscopy (qualified recommendation). 1, 2
Individualize decisions for ages 76-85 years based on: prior screening history, life expectancy >10 years, overall health status, and patient preferences. 1, 2
Discourage screening after age 85 years - harms outweigh benefits regardless of prior screening history. 1, 2
Stop screening at any age when life expectancy falls below 10 years due to comorbidities, as the average time to prevent one colorectal cancer death is 10.3 years from screening initiation. 2, 4, 5
Critical Follow-Up Requirements
All positive non-colonoscopy screening tests MUST be followed by timely diagnostic colonoscopy - this is non-negotiable. 1, 2, 4
Any abnormal FIT, stool DNA test, or imaging finding requires complete colonoscopic evaluation. 1, 2
Quality Metrics for Colonoscopy
When colonoscopy is performed, ensure the following quality standards are met:
Cecal intubation rate >90% in screening populations. 2
Withdrawal time ≥6 minutes. 2
Adenoma detection rate ≥25% in men and ≥15% in women over 50. 2
Physicians must measure and report these quality indicators along with complication rates. 2
Sequential Screening Strategy
When offering screening options, use a sequential approach rather than presenting all options simultaneously:
- First offer colonoscopy every 10 years
- If declined, offer annual FIT
- If declined, offer multitarget stool DNA every 3 years
- If declined, offer CT colonography every 5 years or flexible sigmoidoscopy every 5-10 years 3
This sequential strategy achieves similar overall adherence but results in higher colonoscopy uptake compared to presenting multiple options simultaneously. 3
Common Pitfalls to Avoid
Do not continue screening past age 75 in adequately screened patients - the harms increasingly outweigh benefits with advancing age. 2, 4
Do not screen patients with life expectancy <10 years regardless of age - screening is unlikely to provide benefit. 2, 4, 5
Do not use standard abdominal/pelvic CT scans for screening - these have only 66-86% sensitivity for colorectal cancer and 14.5% sensitivity for polyps, far below dedicated screening protocols. 1
Do not offer blood-based screening tests as they lack the evidence base supporting mortality reduction that stool-based and endoscopic tests possess. 4, 5