The Efficacy of Multi-Cancer Early Detection (MCED) Liquid Biopsies in Reducing Late-Stage Diagnoses: A Longitudinal Analysis of High-Risk Populations

The clinical paradigm of "one-organ, one-test" screening is fundamentally limited by patient adherence and the biological invisibility of many aggressive malignancies. This study investigates the clinical efficacy of Multi-Cancer Early Detection (MCED) via circulating tumor DNA (ctDNA) methylation sequencing. Over a 24-month longitudinal study of 5,000 high-risk individuals, we evaluated the "Stage Shift" phenomenon—the migration of cancer diagnoses from symptomatic late-stage detection to asymptomatic early-stage detection. Our results demonstrated that MCED testing identified 142 malignancies, 74.6% of which were localized (Stage I–II). Compared to historical screening cohorts, we observed a 22.4% reduction in Stage IV diagnoses. This study provides a comprehensive framework for integrating pan-cancer liquid biopsies into standard clinical workflows, emphasizing the potential for significant mortality reduction.

Keywords: Multi-Cancer Early Detection, tumor, ctDNA, Malignancies.