Overview
Estrogen receptor alpha 1 (ESR1) mutations are a key factor in the resistance to endocrine therapy for patients with estrogen receptor-positive (ER+) advanced breast cancer, often leading to disease progression. This study investigates the real-world impact of ESR1 mutations on treatment patterns and clinical outcomes.
The study analyzed 8581 patients with ER+/HER2- metastatic breast cancer in the EHR-derived Flatiron Health Research Database, focusing on those tested for ESR1 mutations during first-line therapy. The results revealed that patients with emerging ESR1 mutations had significantly worse progression-free and overall survival compared to those without such mutations.
Why this matters
The emergence of ESR1 mutations during first-line therapy is linked to poorer outcomes in metastatic breast cancer, underscoring the importance of monitoring these mutations early. This research highlights the need for continuous surveillance of ESR1 mutations, which could guide more tailored and personalized treatment decisions, as well as the unmet need for treatment options that delay progression and improve survival and quality of life for those with ESR1-mutated breast cancer.