Abstract P1-14-06: Survival (S) Following Multi-Modality Treatment of Brain Metastases (BM) in Patients with Breast Cancer

Abstract

Abstract Background: Breast cancer is the second most frequent cause of BM with incidence ranging from 10-20%. The mean S from diagnosis of a brain metastasis varies from 2 to 16 months. With improvements in systemic therapy and targeted agents for control of extracranial disease, effective treatment of BM is an increasingly important goal in breast cancer therapy. We postulated that an aggressive multimodality approach in treatment of BM may be associated with improved survival in this patient population. Methods: Study population included 100 consecutive women with metastatic breast cancer (MBC) who were diagnosed and treated for BM at our institution using craniotomy, stereotactic radiosurgery (SRS), whole brain radiotherapy (WBRT) or a combination of these modalities. Excluded from this analysis are patients with leptomeningeal disease, and those for whom hormone receptor (HR) or HER2 status of the primary tumor is unknown. Data were collected including age at diagnosis of BM; histology, HR and HER2 status of the primary tumor; dates of initial breast cancer diagnosis and CNS relapse; and type of treatment received. Patients were divided into 4 treatment subgroups: those who received WBRT alone (group 1), SRS with or without WBRT (group 2), craniotomy with or without WBRT (group 3), and all modalities of treatment: craniotomy, SRS, and WBRT (group 4). Results: Out of 100 patients, 39 (39%) had triple negative breast cancer (TNBC), 23 (23%) were (HR) positive and HER2-negative, and 38 (38%) were HER2-positive. Among patients with HER2-positive disease, 8 also tested positive for HR. Median age was 50 (54% age less than 50 and 46% above 50). 21 of 23 patients (91%) with HR-positive cancer developed BM after progression of extracranial metastatic disease while 26% of patients (10/39) with TNBC and 29% (11/38) of patients with HER2-positive disease experienced BM as the site of the 1st distant recurrence. In the entire group, median S from BM diagnosis was 15 months (CI 11-18). The median S was statistically different across biological subtypes (p=0.05) with the worst S in TNBC (10.9 months; CI 4.0-15) followed by HER2- positive subtype (19 months; CI 14.9-25.9), followed by HR-positive subtype (27 months; CI 7.9-33.9). Overall, younger patients (below age 50) survived longer than older patients (median 19.9 months (CI 11.9-27.9) vs. 11 months (CI 4.04-16); (p=0.01). Patients who had multimodality treatment (group 4) had a statistically significant (p=0.0002) greater median S (25 months; CI 15-32.9) when compared to those who had WBRT alone (group 1) (3.9 mo, CI 2.9-13). Patients in group 2 and 3 had comparable median S of 15 months (CI 7.9-18) and 13 months (CI 2-34) respectively. The Cox regression model indicated treatment category (p=0.002), biology group (p=0.004) and age (p=0.004) as significantly associated with S. Specifically, patients receiving multimodality therapy (groups 2,3,4) are less likely to die early (HRs=0.5, 0.45, 0.21 respectively) and patients with TNBC have poorer overall S (HR=2.5) compared to HR-positive and HER2-positive patients. Conclusions: Patients with BM from breast cancer have improved S when treated with multi-modality therapy compared with WBRT alone. Older patients and those with TNBC have a worse prognosis. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-14-06.