BMET-05. EVALUATION OF SURVIVAL FOLLOWING STEREOTACTIC RADIOSURGERY FOR BRAIN METASTASES FROM BREAST CANCER

Abstract

We examined the impact of patient- and tumor-specific factors on overall survival in patients with breast brain metastases cancer treated with SRS. We conducted a single-institution IRB-approved retrospective chart review on 47 patients with 158 total breast cancer brain metastases treated with linear accelerator-based SRS between November 2008 and January 2014. Patients included in the study were treated with SRS and had at least one follow-up MRI. Survival was defined as the interval from initial SRS treatment to death. Actual survival was calculated using the Kaplan-Meier method with 95% confidence intervals. Multiple parameters were evaluated for potential relation to survival including prior WBRT, KPS at initial presentation, and histological subtype. Log rank tests were used to evaluate the impact of these parameters on survival. The median follow-up of all metastases was 5.9 months. There was a significant difference in median survival between patients with KPS 90 versus KPS 70 (P=0.032). There was no significant difference in median survival in patients with: prior WBRT (9.59 months, P=0.19); ER positive tumor makers (15.97 months, P=0.56); PR positive tumor markers (20.01 months, P=0.17); HER2 positive tumor markers (14.32 months, P=0.51). Our study supports previous research and further evaluated KPS as significant prognostic factor in brain metastases from breast cancer. Prior WBRT, ER positive, PR positive, and HER2 positive mutation status did not have a significant effect on overall survival following SRS for brain metastases from breast cancer in our study. The assessment of the impact of prior WBRT was limited by the small number of patients with these abnormalities in the study group. These results support the use of SRS for good performance breast cancer patients regardless of marker status.