364PTREATMENT OUTCOMES AND PROGNOSTIC FACTORS FOR PATIENTS WITH BRAIN METASTASES FROM BREAST CANCER: A MULTICENTER COHORT ANALYSIS

ABSTRACT Aim: Brain metastases (BM) are associated with impaired quality of life and have an increasing problem in the management because of progressive neurological impairments. Although BM are less common in patients (pts) with breast cancer, they are associated with considerably poorer prognosis and are less responsive to systemic therapies. Recently, a trend of increased incidence of BM has been noted. To define prognostic factors for BM, compare their clinical courses and prognoses according to the subtypes, and analyze the causes of death. Methods: We retrospectively collected cohort data for 1466 pts diagnosed with BM between 2001 April and 2012 December from 24 institutions of the breast division of the Japan Clinical Oncology Group (JCOG). Results: After exclusion 210 pts' data due to the lack of enough data, overall 1256 pts with BM were evaluated. The median overall survival (OS) was 8.7 months (m) (95% CI, 7.8–9.6). Univariate and multivariate analyses revealed that pts with BM within 6 m of metastatic breast cancer diagnoses, asymptomatic brain disease, or HER2-positive/ER-positive tumors had increased OS. Median OS after BM was 9.3 m (95% CI, 7.2–11.3) for the luminal type, 16.5 m (11.9–21.1) for the luminal-HER2 type, 11.5 m (9.1–13.8) for the HER2 type, and 4.9 m (3.9–5.9) for the triple-negative type. The duration from MBC diagnosis until BM was longer in pts with luminal-type tumors than in pts with luminal-HER2 (HR = 1.24, P= 0.03), HER2 (HR = 1.83, P Conclusions: The prognosis and clinical course of pts before and after developing BM vary according to the subtype. Good prognostic factors for OS included the early detection of BM, asymptomatic brain disease, and HER2/ER-positive status. Focusing on the subtypes can optimize the prevention, early detection, and improved treatment of BM. Disclosure: All authors have declared no conflicts of interest.