ERBB2 and breast cancer: A series of 123 patients with HER2+ breast cancer brain metastases (BCBrM) treated from 1998 to 2015, was subdivided into three cohorts based on the availability of new standard options of anti‐HER2 therapies: 1998 to 2007: trastuzumab; 2008 to 2012: lapatinib; and 2013 to 2015: pertuzumab and T‐DM1.19