10532 Background: Century City Medical Management (CCMM), a network of private primary care practices, implemented MCED testing as part of their cancer screening program. The MCED test detects a cancer signal in cell-free DNA isolated from peripheral blood and predicts the cancer signal origin (CSO). We describe CCMM’s MCED testing workflow and real-world performance. Methods: MCED testing is discussed with all CCMM patients as part of routine care, and shared decision-making guides test utilization. Pts with a positive MCED test result (cancer signal detected) are directed to pursue targeted diagnostic evaluation. This analysis reports on data from 1,949 pts who had 2,922 MCED tests, with results returned between 11/29/21 and 11/24/25. Diagnostic evaluations and clinical outcomes were collected through a Quality Assurance Program via follow-up with ordering providers. All data were deidentified in accordance with HIPAA using the Expert Determination method. The cancer signal detection rate (CSDR) was defined as the proportion of positive MCED tests among all tests administered during the first screening round. Among pts with diagnosed cancers and data available, CSO accuracy (top-two predictions) and median time to diagnosis were calculated. Results of MCED retesting after an inconclusive workup and the frequency of annual MCED screening were evaluated. Results: At the first MCED test (N = 1,949), median age was 63y (IQR: 55-71), 47.5% were female, and the CSDR was 1.03% (95% CI, 0.63–1.58%; 20/1,949). Across all screening rounds, 24 pts had a positive MCED result; 16/24 had ≥12mo follow-up at data cutoff. Among these 16, 3 had an active cancer at testing. Of the 13 pts with ≥12mo follow-up and no active cancer at testing, 7 were subsequently diagnosed with cancer. CSO accuracy was 100% (7/7). None of the diagnosed cancers had USPSTF A/B-recommended screening. 1 diagnosis (symptomatic pt) occurred before MCED results were returned; median time from test results to diagnosis of the other 6 was 62 days (IQR: 30.5-143). 5 pts with an initial positive test but negative CSO-directed workup had an MCED retest and ≥12-mo follow-up. Among these, 4 pts with a negative retest remained cancer-free through the end of follow-up, and 1 with a positive retest was diagnosed with a cancer matching the initial and retest CSO. Among 996 pts tested with >15mo of follow-up, 686 (69.6%) received ≥2 MCED screening tests. The most common interval between consecutive tests was annual (9-15mo), with <10% exceeding an 18-mo interval. Conclusions: MCED testing in a real-world population achieved test performance, CSO accuracy, and diagnostic resolution timelines consistent with prior studies, with high annual screening uptake and clinical utilization of repeat testing after inconclusive CSO-directed workups. The findings support feasible and scalable implementation of MCED testing in primary care.
Sue et al. (Wed,) studied this question.