Central nervous system metastases in women who receive trastuzumab‐based therapy for metastatic breast carcinoma

Metastatic breast carcinoma to the CNS is common among patients receiving trastuzumab-based therapy, including patients responding to therapy outside the CNS. This may be due either to predilection for the CNS by HER-2-positive tumor cells and/or poor penetration of the CNS by trastuzumab or to improved visceral disease control leading to a longer life and onset of late tumor spread to the CNS. Efforts to characterize other risk factors for development of CNS disease, optimal screening algorithms, and new treatment strategies may be warranted.