Age-adapted Variation in Screening Interval of Fecal Immunochemical Test May Improve its Participation and Colonoscopy Acceptance.

Goals: We determined appropriate intervals for administering the fecal immunochemical test (FIT) and performance outcomes in an Asian national colorectal cancer (CRC) screening program.

Background: The optimal interval for FIT in CRC screening is unclear, especially in Asian populations.

Study: Between January 2009 and December 2015, 13,480 individuals aged 50 years or older with an initial negative FIT result underwent 2 rounds of FIT screening at intervals of 1 (annual group, 5333), 2 (biennial group, 7363), or 3 years (triennial group, 784). Positive rates of FIT, colonoscopy acceptance, colonoscopy findings, and detection rates for CRC and advanced neoplasia were compared according to FIT intervals.

Results: The overall positivity rate of FIT in the second screening round was significantly higher in men and in older subjects than in the entire sample. Younger subjects were less likely to undergo annual FIT (36.0% vs. 46.4%, P<0.001). The colonoscopy acceptance rate was decreased in the biennial and triennial groups compared with an annual group among younger subjects (odds ratio, 0.56; 95% confidence interval, 0.33-0.95 for the biennial group vs. odds ratio, 0.19; 95% confidence interval, 0.03-1.37 for the triennial group). Detection rates for CRC and advanced neoplasia in the second round were significantly higher and accompanied by increased FIT screening intervals in older, but not younger subjects.

Conclusions: Age-adapted variation in FIT screening intervals, such as annual screening for elderly subjects and biennial screening for younger subject, may improve FIT participation and colonoscopy acceptance.