Interception versus prevention in cancer screening in a Medicare population: Results from the CRC-MAPS model.

10546 Background: This study examines the impact of detecting cancer (interception) versus adenomas and cancer (prevention + interception) on clinical outcomes in a screen-naive Medicare cohort for a hypothetical colorectal cancer (CRC) screening test or a multicancer early detection (MCED) test that includes CRC. Methods: CRC-MAPS, a validated microsimulation model of the adenoma-carcinoma pathway that reproduced incidence reduction (IR) and mortality reduction (MR) consistent with CISNET models and a randomized controlled trial, was used to simulate perfect adherence to a hypothetical annual screening test among previously unscreened individuals free of diagnosed CRC. Four scenarios were examined: two cancer interception and two cancer prevention + interception. Individuals were screened from age 65 to 75. CRC IR and MR outcomes compared to no screening were aggregated from age 65 until death. Threshold analysis (#5) identified the ≥10mm adenoma sensitivity needed for a base-case cancer interception test (#1) to yield CRC MR equivalent to a near-perfect cancer interception test (#2). Results: The base-case interception scenario (#1) resulted in 5.6% CRC IR and 21.7% MR compared to 5.2% CRC IR and 25.9% MR for the near-perfect interception scenario (#2). The threshold analysis demonstrates that when the base-case interception scenario's ≥10mm adenoma sensitivity is increased from 1% to just 2.43% (#5), the resulting MR is equivalent to a near-perfect interception test. Accordingly, the cancer prevention + interception scenarios (#3, #4) resulted in CRC IR and MR outcomes 9.7-12.9x and 2.5-3.4x (respectively) as favorable as either cancer interception scenario due to adenoma detection. Conclusions: This analysis highlights that even small improvements in the detection of precancerous lesions for certain cancers (e.g., adenomas for CRC), which enable cancer prevention, can yield clinical benefits that meaningfully exceed those from tests that primarily detect cancer. Future studies will explore both benefits and burdens of different screening tests. Moreover, this approach will be applied to better understand the clinical utility of MCED tests. [Table: see text]