Decision-analytic modelling of costs & benefits of adding sigmoidoscopy to CRC screening in Germany

Abstract Background In Germany, a colorectal cancer (CRC) screening programme is in place that entitles individuals to a stool test or colonoscopy. However, less than half of those eligible participate. The inclusion of an additional screening option, such as the evidence-based sigmoidoscopy, could lead to a higher overall participation rate, but also to individuals preferring the additional option to the more effective colonoscopy. The objective of this modelling study is to estimate the impact of offering sigmoidoscopy as an additional option for CRC screening in Germany. Methods A life-time mathematical model (Markov model) is developed to analyse the long-term effects of the additional offer of sigmoidoscopy on benefits (prevalence, mortality, health-related quality of life (HRQoL)), costs, and cost-effectiveness. The model is based on systematic literature reviews and real-world healthcare data. It incorporates disease development, sensitivity and specificity of the options, compliance rates, survival probabilities and background mortality. A discrete choice experiment (DCE) was conducted to estimate the future uptake of the options (stool test, colonoscopy, sigmoidoscopy, no screening) based on stated preferences of n = 666 individuals. Results Adding sigmoidoscopy leads to greater effectiveness of the CRC screening programme in terms of increased screening participation, increased adenoma detection, decreased disease-specific mortality, and improved discounted HRQoL. However, it also incurs higher costs. The incremental cost-effectiveness ratios (ICER) for men and women are €507 per quality-adjusted life year gained (QALYg) and €74 per QALYg, respectively. Conclusions The results indicate that the inclusion of sigmoidoscopy in the German CRC screening programme would be cost-effective and that sigmoidoscopy should be piloted in practice. The expanded programme has the potential to enhance the program’s effectiveness, improve health outcomes, and reduce the burden of CRC. Key messages • Expanding the CRC screening programme may increase overall participation, resulting in higher costs, but also greater effectiveness in detecting more adenomas, reducing mortality, improving HRQoL. • Introducing sigmoidoscopy in Germany appears cost-effective and justifies practical piloting to enhance CRC screening efficacy and health outcomes.