Population health outcomes of blood-based screening for colorectal cancer in comparison to current screening modalities: insights from a discrete-event simulation model incorporating longitudinal adherence

Abstract

Aim Insufficient adherence to colorectal cancer (CRC) screening impedes individual and population health benefits, with about one-third of individuals non-adherent to available screening options. The impact of poor adherence is inadequately considered in most health economics models, limiting the evaluation of real-world population-level screening outcomes. This study introduces the CAN-SCREEN (Colorectal cANcer SCReening Economics and adherENce) model, utilizing real-world adherence scenarios to assess the effectiveness of a blood-based test (BBT) compared to existing strategies. Materials and methods The CAN-SCREEN model evaluates various CRC screening strategies per 1,000 screened individuals for ages 45–75. Adherence is modeled in two ways: (1) full adherence and (2) longitudinally declining adherence. BBT performance is based on recent pivotal trial data while existing strategies are informed using literature. The full adherence model is calibrated using previously published Cancer Intervention and Surveillance Modeling Network (CISNET) models. Outcomes, including life-years gained (LYG), CRC cases averted, CRC deaths averted, and colonoscopies, are compared to no screening. Results Longitudinal adherence modeling reveals differences in the relative ordering of health outcomes and resource utilization, as measured by the number of colonoscopies performed per 1,000, between screening modalities. BBT outperforms the fecal immunochemical test (FIT) and the multitarget stool DNA (mtsDNA) test with more CRC deaths averted (13) compared to FIT and mtsDNA (7, 11), more CRC cases averted (27 vs. 16, 22) and higher LYG (214 vs. 157, 199). BBT yields fewer CRC deaths averted compared to colonoscopy (13, 15) but requires fewer colonoscopies (1,053 vs. 1,928). Limitations Due to limited data, the CAN-SCREEN model with longitudinal adherence leverages evidence-informed assumptions for the natural history and real-world longitudinal adherence to screening. Conclusions The CAN-SCREEN model demonstrates that amongst non-invasive CRC screening strategies, those with higher adherence yield more favorable health outcomes as measured by CRC deaths averted, CRC cases averted, and LYG.