Background: Breast cancer (BC) is the second most common cause of brain metastasis in the United States. Compared to whole brain radiation therapy (WBRT), treatment with gamma-knife radiosurgery (GKRS) offers a better chance at neurocognitive preservation. The goal of our retrospective study is to report the overall survival (OS) in patients receiving GKRS and to identify factors that improve survival outcomes.
Methods: The records of 80 patients with primary BC treated with GKRS at the Yale Comprehensive Cancer Center between 2000 and 2013 were reviewed. OS was calculated from the date of first GKRS treatment. Other factors studied were age, Karnofsky performance status (KPS), tumor subtype, having WBRT and/or surgical resection pre- or post-GKRS, and number of brain metastases treated with GKRS.
Results: Median age was 56.2 years. OS from first GKRS was 13.1 months (95% CI 7.6-21.9). On univariate analysis, improved survival was associated with HER-2 subtype (p = 0.026), KPS score > 80 (p = 0.009), and good control of systemic disease at time of GKRS (p = 0.020). Multivariable analysis detected a significantly longer survival with HER-2 positivity (HR 0.22, 95% CI 0.06-0.76, p = 0.017) and a strong trend in patients with craniotomy prior to GKRS (HR 0.13, 95% CI 0.01-1.11, p = 0.06).
Conclusions: GKRS is a promising therapy for treating brain metastasis from BC, particularly in those with HER-2 positivity and high-performance scores even in those patients with > 5 brain metastases. Furthermore, GKRS may also be a useful adjunct to surgical resection in such patients. High rates of neurological death remain from BC brain metastases; however, and need further investigation.
Keywords: Brain; Breast; Cancer; Gamma-knife; Metastasis; Radiosurgery; Stereotactic.