Summary

USPSTF 2021 recommendations on colorectal cancer screening in average-risk asymptomatic adults. New in this update: screening start age lowered from 50 to 45 years (Grade B for ages 45-49). Screening ages 50-75 remains Grade A; selective screening ages 76-85 remains Grade C; discontinue after 85. Multiple stool-based and direct visualization strategies are endorsed without ranking.

Key Recommendations

Screen all average-risk adults aged 50-75 years for colorectal cancer (Grade A).
Screen average-risk adults aged 45-49 years for colorectal cancer (Grade B) — new in 2021.
Selectively screen adults aged 76-85 years based on overall health, prior screening history, and patient preferences (Grade C); do not screen after age 85.
Recommendation applies to asymptomatic average-risk adults — excludes those with prior CRC, adenomatous polyps, IBD, or known hereditary syndromes (Lynch, FAP).
Acceptable screening strategies: annual FIT or HSgFOBT, sDNA-FIT every 1-3 years, CT colonography every 5 years, flexible sigmoidoscopy every 5 years (or every 10 years plus annual FIT), or colonoscopy every 10 years.
Any positive non-colonoscopy screening test must be followed by colonoscopy to achieve screening benefit.
Do not use serum tests, urine tests, or capsule endoscopy for CRC screening (insufficient evidence).
Apply the same starting age of 45 to Black adults (USPSTF does not make a separate race-based recommendation despite higher CRC incidence/mortality in Black adults).
Persons with Lynch syndrome, FAP, or strong family history require specialized screening outside this recommendation.
Tests are not ranked; choose strategy based on patient preference, adherence likelihood, and local resources.

Thresholds & Doses

Start screening: age 45 years (average risk).
Routine screening through age 75 years.
Ages 76-85: individualized/selective screening.
Discontinue screening after age 85 years.
HSgFOBT: every 1 year (requires 3 stool samples + dietary restrictions).
FIT: every 1 year (single sample; positivity cutoff 20 μg hemoglobin/g feces in CISNET modeling).
sDNA-FIT (multitarget stool DNA + FIT): every 1-3 years.
CT colonography: every 5 years.
Flexible sigmoidoscopy alone: every 5 years.
Flexible sigmoidoscopy every 10 years + annual FIT.
Colonoscopy: every 10 years.
Colonoscopy harms: ~14.6 major bleeds and 3.1 perforations per 10,000 screening colonoscopies; 17.5 bleeds and 5.4 perforations per 10,000 follow-up colonoscopies.
CT colonography radiation dose: 0.8-5.3 mSv per exam; extracolonic findings in 1.3-11.4% of exams.
Estimated benefit screening ages 45-75: 286-337 life-years gained, 42-61 CRC cases averted, 24-28 CRC deaths averted per 1000 screened.

Citations

Recommendation Summary table — age-stratified grades (A for 50-75, B for 45-49, C for 76-85).
Practice Considerations: Screening Intervals — list of recommended strategies and frequencies.
Practice Considerations: Starting and Stopping Ages — rationale for age 45 start and age 85 stop.
Update of Previous USPSTF Recommendation — change from 2016 (lowered start age from 50 to 45).
Table 1 — Characteristics of recommended screening strategies including FIT 20 μg threshold.
Supporting Evidence: Harms of Screening — colonoscopy bleeding/perforation rates and CT colonography extracolonic findings.
Practice Considerations: Screening in Black Adults — rationale for uniform age 45 start.
Patient Population Under Consideration — exclusion of Lynch syndrome, FAP, IBD, prior CRC/adenoma.