1 Potential Effectiveness and Cost-Effectiveness of Tailoring Screening to Predicted Colorectal Cancer Risk

Abstract

Background: Tailoring colorectal cancer (CRC) screening to predicted CRC risk could improve effectiveness and cost-effectiveness. CRC risk prediction tools with modest discriminatory ability exist, but are not used widely. Aims: To explore the potential effectiveness and cost-effectiveness of tailored CRC screening. Methods: We adapted our validated decision analytic model of CRC screening to explore tailored screening, where different strategies were recommended for different predicted risk levels defined by the risk tool. We evaluated the effectiveness (quality-adjusted life-years [QALYs]/person) and cost-effectiveness (cost/ QALY gained) of tailored screening as a function of a tool's predictive ability and cost. In the base case, we assumed a beta distribution for true lifetime CRC risk in the general population with mean 5.9% and 95% at =12% based on threshold analyses showing that less and more intensive colonoscopic screening in these groups, respectively, was cost-effective. Base Case Results With a Perfectly Performing and Free Prediction Tool : Colo was cost-saving vs. no screening. Even though Colo yielded fewer QALYs/person than colo q10, it was less costly than Coloq10, and the slight advantage of colo q10 cost $147,000/QALY gained. Colo/FIT yielded more QALYs/person than FIT q1 at $48,000/QALY gained (Table 1). CRC cases, deaths and colonoscopy demand are shown in Table 1. Sensitivity Analyses: As the level of misclassification increased, the effectiveness and costeffectiveness of tailored screening decreased; e.g. with 20% misclassification, tailored screening was not cost-effective at thresholds of $50,000-$100,000/QALY gained (Table 1). Even modest costs for the prediction tool impacted its cost-effectiveness substantially (Table 1). The specific results depended on the shape (bimodal vs. unimodal) and variability of the true CRC risk distribution. Conclusions: A highly accurate and inexpensive CRC risk prediction tool could yield cost savings with minimal decrease in effectiveness when used to tailor colonoscopic screening, or improve effectiveness at acceptable costs when used to shift higher risk persons in a FIT program to colo q5. Even low misclassification levels or prediction tool costs affect the effectiveness and cost-effectiveness of tailored screening substantially. Clinical and Economic Outcomes of Tailored CRC Screening, Ages 50-80