Stereotactic Radiosurgery Versus Whole Brain Radiation Therapy: A Propensity Score Analysis and Predictors of Care for Patients With Brain Metastases From Breast Cancer

Background: Metastases to the brain occur in 10%-16% of patients with breast cancer, with incidence reportedly increasing. Historically, brain metastases (BM) have been treated with whole-brain radiation therapy (WBRT), but stereotactic radiosurgery (SRS) is an increasingly favored treatment option. In this study we used a population-level database to compare patterns of care and survival between WBRT and SRS for BM from breast cancer. Materials and Methods: The National Cancer Database was used to select patients treated with radiation for BM from primary breast cancer. Groups were classified on the basis of the modality of radiation delivered to the brain and compared across several demographic factors. A Kaplan–Meier survival curve and Cox multivariate analysis were used to compare overall survival. A matched analysis using propensity scores was used to further reduce confounders and compare survival. Results: The treatment groups were significantly different across several socioeconomic variables including income, insurance status, and treatment setting. The percentage of patients who received SRS increased dramatically in the second half of the analyzed time period (P <.001). Unadjusted median survival was significantly longer for patients who received SRS versus those who received WBRT (P <.001). This finding persisted after propensity score-matching. Conclusion: Receipt of SRS was associated with different socioeconomic variables and longer overall survival compared with WBRT, highlighting the need for less toxic treatment for patients who are now living longer. The results revealed important socioeconomic differences between patients selected for SRS versus WBRT and emphasizes disparities in access to modern radiation techniques across the United States.