THE ROLE OF BRAIN METASTASIS FREE INTERVAL IN PATIENTS WITH BRAIN METASTASES OF BREAST CARCINOMA

In patients with brain metastases of breast cancer (BMBC), time interval between primary tumor diagnosis and appearance of first brain metastasis varies widely. This brain metastasis free interval (BMFI) is a readily available parameter and has been suggested by some to be of prognostic value. The aim of this study is to compare characteristics between patients with different BMFIs and determine if BMFI is a prognostic factor for overall survival in BMBC. We retrospectively reviewed a multi-institutional neurosurgical/radiation oncological database of female patients who were treated for BMBC between 1996 and 2017. Cox proportional hazards model and Kaplan-Meier survival curves were used to determine prognostic value for survival. A total of 503 patients were included. Median age at first brain metastasis was 52 (interquartile range (IQR) 45–58). Median BMFI was 38 months (IQR: 18 - 66) and median overall survival was 17 months (IQR 8 - 31). In univariate cox proportional hazards model, age at brain metastasis, tumor subtype, and the presence of liver or lung metastases were significantly associated with overall survival. BMFI > 3 years was not associated with a longer overall survival (hazard ratio (HR) = 1.13, p = .21). In multivariate analysis, only subtype (luminal-her2 versus triple negative, HR = .77, p = .02) and the presence of liver metastases (HR = 1.36, p = .01) were prognostic for overall survival. Again, no significant association with BMFI was found (HR = .99, p = .91). CONCLUSIONS: In this large, retrospective cohort, patients with a long BMFI had a similar overall survival when compared to those with a shorter interval.