Yield and Effectiveness of 2-Sample Fecal Immunochemical Test–Based Screening Program for Colorectal Cancer

Abstract

Background and Aims

Colorectal cancer (CRC) incidence and mortality of China account for nearly 30% of the global attributable fraction. We aimed to estimate the yield and effectiveness of a 2-sample fecal immunochemical test (FIT)–based screening program in China.

Methods

Eligible individuals were invited for 2-sample FIT between 2007 and 2021, with positive ones (cutoff 40 μg/g before 2013 and 20 μg/g thereafter) referred for colonoscopy. Participation rates, detection rates, and positive predictive values were calculated. Participants were classified into: FIT+/colonoscopy compliers, FIT+/colonoscopy noncompliers, and FIT– as control subjects. We compared CRC incidence and mortality and calculated the age reaching comparable risk.

Results

Among 246,349 invitees, 150,524 (61.10%) participated in 2-sample FIT, with 16,994 (11.29%) identified as FIT+; 12,816 (75.41%) underwent colonoscopy, yielding a detection rate and positive predictive value of 0.57% and 6.70% for advanced neoplasia, respectively. Median follow-up was 10.58 years. Compared with FIT– participants, CRC incidence and mortality were relatively similar among FIT+/colonoscopy compliers with hazard ratios of 0.94 (95% confidence interval [CI], 0.75–1.19) and 1.62 (95% CI, 1.09 to 2.41) but higher among noncompliers, with hazard ratios of 3.52 (95% CI, 2.85–4.34) and 4.41 (95% CI, 2.96–6.55). Taking CRC incidence and mortality risk of FIT– participants at 50.0 years of age as the benchmark, FIT+/colonoscopy compliers reached same risk at 50.6 and 46.1 years of age, while noncompliers reached the same risk at 38.0 and 37.9 years of age, respectively.

Conclusions

Two-sample FIT could effectively identify high-risk populations, and colonoscopy compliance is associated with a lower risk of CRC incidence and mortality. This strategy might facilitate CRC screening practice in countries with large populations.