Circulating Tumor DNA as a Predictive Biomarker for Treatment Response in Metastatic Breast Cancer

This study evaluates the clinical utility of serial circulating tumor DNA (ctDNA) profiling in predicting treatment response among patients with metastatic breast cancer undergoing targeted therapy. Across a cohort of 214 patients, early ctDNA clearance at six weeks correlated strongly with progression-free survival, outperforming conventional imaging-based response criteria in both sensitivity and lead time. These findings support the integration of liquid biopsy monitoring into routine precision oncology workflows, enabling earlier treatment adaptation and reducing unnecessary exposure to ineffective regimens.