Using Biomarker Results to Guide Treatment in ER-Positive, HER2-Negative Metastatic Breast Cancer

In this segment, Dr. Gregory Vidal explains how biomarker test results directly influence treatment decisions in ER-positive, HER2-negative metastatic breast cancer. He describes how identifying specific molecular alterations helps clinicians tailor therapy to the biology of an individual patient’s cancer. For example, the presence of certain mutations, such as ESR1 mutations that may develop after prior endocrine therapy, can inform the selection of targeted therapies or estrogen receptor antagonists. Dr. Vidal emphasizes that biomarker-driven decision-making allows for a more personalized approach, helping to optimize treatment effectiveness while minimizing unnecessary therapies. He also notes that biomarker testing supports strategic sequencing of therapies over time as the disease evolves. By understanding how biomarker results shape clinical choices, patients can better appreciate why their treatment plan may change throughout the course of ER-positive, HER2-negative metastatic breast cancer and how those adjustments are grounded in the underlying biology of their disease.