Treatment of Breast Cancer Brain Metastases.

Approximately 10% to 15% of women with metastatic breast cancer will develop brain metastases. Treatment options for these women remain limited, particularly at the time of central nervous system (CNS) relapse following completion of initial CNS-directed therapy. Historically, prior studies have broadly examined systemic treatments for breast cancer brain metastases with mixed, but overall disappointing, results. More recently, studies have increasingly selected patients based on breast cancer subtype and have examined novel, targeted agents that have preclinical suggestion of blood-brain barrier penetration. Correlative science objectives, with both tissue-based and novel imaging endpoints, are more frequently incorporated into trials of this nature, with the goal of enhancing our understanding of possible predictors of response. This review summarizes the current and emerging data on systemic therapy for breast cancer brain metastases and provides a framework for future directions in treating this clinically-challenging entity.