Beyond breast specific-Graded Prognostic Assessment in patients with brain metastases from breast cancer: treatment impact on outcome

Brain metastases are a serious relatively common complication of breast cancer. We evaluated prognostic factors for survival after diagnosis of brain metastases from breast cancer in a contemporary cohort of patients. Patients diagnosed with breast cancer brain metastases at our institution between 1999 and March 2016 were evaluated. Overall survival was defined as time from brain metastasis diagnosis to death or last follow-up. Patients were classified according to the Breast cancer-specific Graded Prognostic Assessment (BS-GPA), based on age, Karnofsky performance score and breast cancer phenotype. 181 patients were identified. Tumor phenotype distribution was as follows: triple negative (TN, 18.8%), hormone receptor (HR)-HER2+ (16.6%), HR+HER2+ (23.2%) and HR+HER2- (30.9%), not available (10.5%). Median overall survival from brain metastasis diagnosis was 7.7 mos (95% CI 5.4-10.0 mos). Although TN patients experienced the worse outcome, no significant difference was observed across tumor phenotypes (median 5.1, 7.7, 11.0 and 8.6 months in TN, HR-HER2+, HR+HER2+, HR+HER2-, p = 0.081). The BS-GPA index was significantly associated with overall survival (median 18.8, 8.8, 6.2 and 3.6 months, respectively, for BS-GPA categories 3.5-4, 2.5-3, 1.5-2 and 0-1, p = 0.014). Increased number of local treatments for brain metastasis (radiotherapy or neurosurgery) or the administration of systemic therapy after brain metastasis diagnosis were also significant predictors of better overall survival (p < 0.001) and, when evaluated in multivariate analysis with BS-GPA, both added independent prognostication beyond BS-GPA. Patient-related features, tumor phenotype and multimodal treatments all independently contribute to modulate prognosis of patients diagnosed with breast cancer brain metastases.