Treatment patterns and real world clinical outcomes in ER+/HER2-post-menopausal metastatic breast cancer patients in the United States

Background: With several new therapies becoming available, treatment of metastatic breast cancer (mBC) is evolving. The objective of this study is to describe patient characteristics, treatment patterns and real-world clinical outcomes in post-menopausal women with ER+, HER2-mBC and to obtain insight into patient outcomes and potential unmet needs with current therapies. Methods: The current study is a physician survey followed by a retrospective chart review of patient medical records by physicians in the US between March and April 2015. One hundred three physicians were asked to complete an online survey aiming to understand their satisfaction and expectations with current available treatments and potential areas of unmet need for mBC patients. Medical records from 178 females were extracted for the chart review. Using these data from medical records, patient characteristics and treatment patterns were analyzed descriptively. Time to progression (TTP) on first line, and progression-free survival (PFS) on second and third line of therapy were analyzed using the Kaplan-Meier method. Results: Sixty-seven percent (n = 119) of patients had metastatic disease at initial diagnosis of breast cancer. Mean age at chart data extraction was 65.8 (SD: 9.4) years. Aromatase inhibitors (AIs) were prescribed for 58% and around 13% of patients in first line and second line, respectively. Chemotherapy was prescribed to 14% in first line and 31% in second line. Median TTP on first line therapy was 12 months for patients receiving AIs as compared to 7.9 months for patients receiving chemotherapy. Across all treatment lines, bone pain and fatigue were reported as the main symptoms associated with disease progression which had an impact on patient quality of life. Physicians expressed that prolonging life was deemed the most important treatment goal, followed by preservation or improvement of quality of life. Conclusion: In this study the majority of patients received endocrine therapy as first line treatment and current therapies still resulted in a short time to progression in first line. Results from the chart review and the physician survey highlight a quantitative unmet need for more effective treatments which delay disease progression and improve survival outcomes while maintaining quality of life.