Radiation therapy for breast cancer (BC) with central nervous system (CNS) metastases: A contemporary experience at Memorial Sloan-Kettering Cancer Center (MSKCC).

Abstract

144 Background: Many of the well-studied prognostic factors for patients with breast cancer (BC) brain metastases (BM) are based on data from an era when stereotactic radiosurgery (SRS) was not commonly used. In this study, we examined patient characteristics and outcomes for patients with CNS metastases who recently underwent cranial radiation at MSKCC. Methods: 173 consecutive BC patients with CNS metastases receiving SRS or WBRT from January 2009 to December 2011 were identified. Clinico-pathologic and treatment information was obtained by retrospective review. Patient characteristics and associations were evaluated. Time from BM to death was evaluated by Kaplan-Meier and log-rank tests. Results: Of 173 patients (2 missing HER2 status), the subgroups were: HR+HER2-: 77 (45%), HR+HER2+: 28 (16%), HR-HER2+: 17(10%), and HR-HER2-(TNBC): 49 (29%). 121 had whole brain radiotherapy (4 with prior SRS), and 50 had SRS only. The use of SRS differed by subtype (overall Fisher’s exact p=0.02): 59% (HR-HER2+), 33% (TNBC), 29% (HR+HER2+), 21% (HR+HER2-). There were a total of 110 deaths. The median follow-up for survivors was 19mo (range: 6-67mo). The median time from BM to death for all patients was 17.5mo (95% confidence interval: 14-20mo): 41mo (HR-HER2+), 63mo (HR+HER2+), 14.5mo (HR+HER2-), 14mo (TNBC; log-rank test p=0.0001). Conclusions: Although HER2+ and TNBC subtypes are associated with a higher risk of BM, we noted a higher prevalence of HR+HER2- disease in BC patients with CNS metastasis, a group currently understudied. The prognostic information for time from BM to death differs according to subtype and may be important for future planning of clinical trials. Further evaluation of factors related to these outcomes is ongoing.