OBJECTIVES: Colorectal cancer (CRC) screening has been shown to be effective and cost-saving. However, the trend of rising incidence of early-onset CRC challenges the current national screening program solely for people ≥50 years in Germany, where extending the screening to those 45-49 years might be justified. This study aims to evaluate the cost-effectiveness of CRC screening strategies starting at 45 years in Germany.

METHODS: DECAS, an individual-level simulation model accounting for both adenoma and serrated pathways of CRC development and validated with German CRC epidemiology and screening effects, was used for the cost-effectiveness analysis. Four CRC screening strategies starting at age 45, including 10-yearly colonoscopy (COL), annual/biennial fecal immunochemical test (FIT), or the combination of the two, were compared with the current screening offer starting at age 50 years in Germany. Perfect screening adherence was assumed. For each strategy, a cohort of 100,000 individuals with average CRC risk was simulated from age 20 until 90 or death. Outcomes included quality-adjusted life years gained (QALYG), and total incremental costs considering both CRC treatment and screening costs. A 3% discount rate was applied and costs were in 2021 Euro.

RESULTS: Initiating 10-yearly colonoscopy-only or combined FIT+COL strategies at age 45 yielded incremental gains of 7-28 QALYs with incremental costs of €27,280 - €69,025 per 1000 individuals, compared to the current strategy. The incremental cost effectiveness ratios (ICER) ranged from €990 to €9,394 per QALYG. FIT-only strategy was dominated by the currently implemented strategy. The findings remained consistent across probabilistic sensitivity analyses.

CONCLUSIONS: The cost-effectiveness findings support initiating CRC screening at age 45 with either colonoscopy alone or combined with FIT, demonstrating substantial gains in quality-adjusted life years with a modest increase in costs. Further research should consider real-world adherence rates and budget implications, as well as investigate risk- or patient preference-based screening.