A 62-Year-Old Woman with HR+ HER2-low Metastatic Breast Cancer and Lung, Liver, and Bone Metastases and Using Biomarker Testing to Guide Treatment Selection

Virginia Kaklamani, MD, DSc, presents a case of metastatic breast cancer, initially responsive to first-line aromatase and CDK4/6 inhibitors, that progressed after 32 months. She explores using biomarker testing to identify ESR1 and other actionable mutations potentially causing endocrine resistance, guiding the transition to second-line therapy.