Cost-Effectiveness Analysis of Annual vs Biennial Fecal Immunochemical Testing for Colorectal Cancer Screening in Japan: A Microsimulation Analysis

Background The optimal screening interval for fecal immunochemical testing (FIT) in Japan remains uncertain. Objective This study aimed to evaluate the cost-effectiveness of biennial FIT screening compared with annual FIT screening to inform future national guidelines. Methods We developed a microsimulation model of a cohort of 100 000 average-risk Japanese individuals aged 40 years and older followed over a 60-year horizon from a healthcare payer perspective. Two screening methods were compared: the current annual FIT and biennial FIT. Effectiveness was measured in quality-adjusted life-years (QALYs), and costs were measured in 2024 Japanese yen. Results Annual FIT screening was dominant, resulting in lower total costs (¥408 058 vs. ¥451 407) and higher QALYs (26.483 vs 26.440) compared with biennial screening. Probabilistic sensitivity analysis indicated that annual screening was cost-effective in 92.7% of iterations at a WTP threshold of ¥5 million per QALY. Conclusions The analysis indicated that annual FIT screening was dominant over biennial screening, because of its lower costs and higher QALY yield. These findings were supported by probabilistic sensitivity analysis. Although annual FIT screening is generally superior to biennial screening in Japan and provides greater health benefits at lower costs, future policies should aim to address endoscopic capacity constraints to ensure program sustainability.