We present a 63-year-old female with estrogen receptor (ER)-positive Her2− breast cancer...She achieved complete intracranial remission and prolonged survival by whole-brain radiotherapy (WBRT) concomitant with intrathecal methotrexate (MTX)….Our case indicated ER+ HER2− LM-BC can be effectively treated by radiotherapy with concurrent intrathecal chemotherapy (IC).