Cost-utility analysis of expanding the colorectal cancer screening policy in Flanders

Abstract
Objective
Since 2013, Flanders has introduced a screening programme for colorectal cancer for all citizens aged between 50 and 74 years. The objective of this study was to assess the cost-utility of an expansion of the colorectal cancer screening policy in Flanders (Belgium) and to place these findings in the international context.

Methods
Cost-utility analysis using high-detail data about screening participation, screening results, and epidemiological data, a Markov cohort model has been constructed to study long-term costs and effects. A cost-utility analysis was performed as a three-way comparison between current, expanded (from age 45 years), and no screening scenarios, from a societal and healthcare perspective. Robustness was assessed by both one-way and probabilistic sensitivity analyses.

Results
Analyses show that both current and expanded screening result in quality-adjusted life years (QALY) gains and are mostly cost-saving. Overall, 97.5% of Incremental Cost-Effectiveness Ratios (ICERs) remained well below € 2000 per QALY for all comparisons. Parameters related to the colonoscopy that follows a positive test result such as compliance and cost are especially impactful on the cost-effectiveness.

Conclusions
Screening participation and screening costs have remained comparatively stable, making colorectal cancer screening a cost-effective (dominant) policy. Expanding the screen age to 45 years is also cost-effective (dominant) compared with current screening, albeit with a slimmer margin.