Impact of offering blood-based testing alongside existing modalities for colorectal cancer screening among those who previously declined screening: an economic evaluation.

[AIM] Inadequate adherence to colorectal cancer screening reduces individual and population level health benefits. Blood-based tests offer a new modality that may help patients overcome barriers, but there are concerns about the impact of patients switching from existing guideline-recommended screening modalities. This study estimates the population health outcomes and cost-effectiveness of offering blood-based testing using a validated individual-level simulation model based on patient preference evidence from randomized controlled trials.

[MATERIALS AND METHODS] In this study, a validated discrete-event simulation model was used to evaluate the performance of different combinations of colorectal cancer screening strategy preferences per 10,000 screened individuals beginning at age 45. Preferences for screening options were informed by randomized controlled trials of patients with and without the option of blood-based testing. Adherence to initial patient preferences over a simulated lifetime was modeled as: (1) assumed 100% adherence and (2) longitudinal using a calibrated model. Simulated outcomes included clinical outcomes and cost-effectiveness from a healthcare sector perspective. A strategy was deemed cost-effective at a willingness-to-pay threshold of $100,000 per quality-adjusted life-year gained.

[RESULTS] The introduction of blood-based testing to an unscreened population with evidence from randomized controlled trials is projected to increase colorectal cancer deaths averted by 35% to 116% and from 68% to 247% relative to no screening, for stated preference and revealed preference scenarios, respectively. These outcomes are cost-effective, with incremental cost-effectiveness ratios ranging from $63,994 to $85,497 and from $30,464 to $54,764 across stated preference and revealed preference scenarios, respectively.

[LIMITATIONS] Given limited data, natural history and real-world longitudinal adherence to screening are based on evidence-informed assumptions.

[CONCLUSIONS] Using a simulation model to extrapolate data from two recent trials, we demonstrate that the introduction of blood-based tests has the potential to lead to cost-effective increases in the number of CRC deaths averted among the unscreened population.