HR-Positive Breast Cancer: Interpreting ctDNA Dynamics and Clinical Benefit in SERENA-6

This segment explores deeper clinical interpretations of the SERENA-6 trial, particularly focusing on circulating tumor DNA dynamics and their relevance in hormone receptor–positive, HER2-negative metastatic breast cancer. Dr. Adam Brufsky highlights the observed reductions in ESR1 mutations allele frequency with treatment change, suggesting that molecular progression may precede radiographic progression in clinical practice.

Dr. Mabel Mardones underscores the clinical significance of delaying disease progression and extending time to chemotherapy or antibody-drug conjugates, noting the meaningful impact on patient quality of life. She emphasizes the value of maintaining patients on oral therapies when possible.

Dr. Lisa Raff raises important questions regarding the interpretation of variant allele frequency and whether thresholds may guide treatment decisions. Overall, this segment highlights both the promise and remaining uncertainties of ctDNA-guided intervention in clinical practice.