HR-Positive Breast Cancer: SERENA-6 and ctDNA-Guided Early Intervention

This segment focuses on the clinical implications of the SERENA-6 trial and its evaluation of circulating tumor DNA–guided treatment switching in hormone receptor–positive, HER2-negative metastatic breast cancer. Dr. Adam Brufsky introduces the trial within the context of ongoing regulatory and clinical debate regarding biomarker-driven intervention prior to radiographic progression.

Dr. Hope S. Rugo provides an overview of the study design, highlighting the identification of emergent ESR1 mutations during endocrine therapy and the strategy of switching treatment at the point of molecular progression. She discusses key findings, including improvements in progression-free survival and notable differences in patient-reported outcomes, particularly related to pain. The discussion also raises important considerations regarding treatment sequencing, timing of intervention, and the clinical relevance of early switching. Overall, this segment highlights the potential and ongoing debate surrounding ctDNA-guided therapeutic decision-making.