Factors Associated with Survival in Patients with Breast Cancer (BC) Brain Metastasis (BM)
Rong Li, Kui Zhang, Gene P Siegal, Shi Wei. University of Alabama at Birmingham, Birmingham, AL
Background: Up to 15% of patients with stage IV BC will eventually develop BM in the course of their disease, which has become a major clinical problem due to the limited effective systemic therapies. This substantiates the urgent need for better understanding of risk factors for developing BM to obtain the largest benefit from prevention and to utilize optimal treatment strategies. The aim of study was to determine the clinicopathologic factors significantly associated with survival in these patients.
Design: We analyzed all BC patients with BM from 1997 to 2012 at our institution. The clinicopathologic factors were recorded, including age, race, tumor type, histologic grade, receptor status, stage at diagnosis and presence of other organ metastases to identify factors significant for overall survival (OS), BM free survival (BMFS) and post BM survival (PBMS) by utilizing the Cox proportional hazard model.
Results: Of all patients with stage IV BC in the study period, 88 had BM at diagnosis (6) or subsequently (82). There were significantly higher proportions of HER2 subtype (25%) and triple-negative (TN) BC (26%) among these patients compared to the general BC population. High grade and stage IV at diagnosis were significantly associated with poor OS by univariate analysis, and the former remained significant in multivariate analysis (p<0.01). Lobular BC, high grade, stage IV at diagnosis and non-luminal subtypes were significantly associated with BMFS by univariate and multivariate analysis (p=0.01, 0.02, <0.0001 and <0.01, respectively), whereas BMFS did not differ significantly between HER2 and TNBCs. The mean BMFS of the three BC subtypes were 36.5, 28.4 and 30 months, respectively. While histologic grade, the presence of other organ metastasis and BC subtype were significantly associated with PBMS by univariate analysis, only histologic grade remained significant in multivariate analysis (p=0.02).
Conclusions: While histologic grade was universally associated with survival in BC patients with BM, BMFS differed significantly between tumor types, stage at diagnosis and BC subtypes. In addition to TNBC, a known risk factor of developing BM, HER2 subtype showed a similar incidence of BM and BMFS, likely reflecting that HER2 targeted therapy improves systemic disease control while unmasking BM in these patients. The lack of significance in OS by other factors is likely due to relatively shorter follow-up in a significant proportion of the patients. Nonetheless, this analysis might help in stratifying patients into prognostically significant categories for optimal treatment decision making.
Wednesday, March 6, 2013 1:00 PM
Poster Session VI # 250, Wednesday Afternoon