Systemic Therapy in the Setting of Central Nervous System (CNS) Metastases in Breast Cancer

Purpose of Review: Over 25% of patients with metastatic breast cancer will develop brain metastases. Recent advances in systemic therapy, especially molecularly targeted agents, have improved control of extracranial disease, but have had limited effect on intracranial disease. In this review, we discuss the barriers and challenges associated with employing systemic therapy to treat brain metastases. We also provide an overview of current systemic therapy used as standard of care in all subtypes of breast cancer that have metastasized to the brain, as well as describe novel agents that are currently under study in preclinical models or clinical trials. Recent Findings: While there are few systemic therapies that are standard of care for the treatment of breast cancer brain metastases, there are many novel agents currently in development or under active investigation. Detailed genomic analysis has led to a better understanding of the molecular aberrations that drive metastasis in the different subtypes of breast cancer, leading to rational approaches to the development of targeted molecular therapy. Summary: The most promising systemic therapeutic modalities for treating breast cancer brain metastases utilize targeted molecular agents or molecular exploitation of the blood-brain barrier in combination with cytotoxic chemotherapy to enhance entry into the CNS. © 2017, Springer Science+Business Media, LLC.