Benefits of colorectal cancer screening using FIT with varying positivity thresholds by age and sex.

Abstract

Background: Fecal immunochemical test (FIT) performance for colorectal cancer (CRC) screening varies by age and sex, yet most FIT-based screening programs use uniform thresholds. This study assessed the potential benefits of stratifying FIT thresholds based on age and sex.

Methods: We conducted a meta-analysis of FIT sensitivity and specificity at various positivity thresholds by age and sex. We then used these estimates in two microsimulation models of CRC and projected lifetime clinical outcomes, incremental costs, and quality-adjusted life-years gained (QALYG) from age- and sex-stratified FIT strategies. FIT thresholds ranged from 10 to 50 µg hemoglobin/g feces (µg/g).

Results: For current uniform FIT screening (20 µg/g), models projected 85.67 to 122.15 QALYG at incremental costs of -$982 to $504 per 1,000 individuals compared to no screening. At equivalent costs to current uniform screening, only one model found stratified FIT approaches cost-effective, yielding a marginal increase of 1.04 and 1.10 QALYG/1,000 females and males, respectively. At a willingness-to-pay threshold of $100,000/QALYG, both models found stratified FIT cut-offs to be the best strategy, with cut-offs being equal or higher for men and lowest at older ages. Uniform strategies showed comparable effectiveness, falling within one quality-adjusted life day per person of efficient strategies at up to $112 more per person. Results were sensitive to FIT test performance characteristics and one-time setup costs.

Conclusion: Stratifying FIT thresholds by age and sex may be cost-effective compared to current screening. However, the gain in expected health benefits with stratified FIT screening is likely small.