Successful therapy by WBRT with concurrent intrathecal MTX for isolated leptomeningeal metastasis in ER+ HER2− breast cancer: case report

Abstract

Abstract Background: Leptomeningeal metastasis(LM) is a relatively rare but devastating manifestation of breast cancer, with an incidence rate of approximately 5%, half of these patients suffer from simultaneous brain metastasis. LM in breast cancer (LM-BC) carries a poor prognosis, with a median overall survival of approximately four weeks without treatment. However, there is no standardized therapy for LM yet. Case presentation: We present a 63-year-old female with estrogen receptor (ER)-positive Her2− breast cancer after multiline treatment, her pathological examination of the cerebrospinal fluid (CSF) revealed numerous malignant cells, magnetic resonance imaging(MRI) of the brain with contrast demonstrated intense enhancement of the leptomeninges, without brain metastasis. She achieved complete intracranial remission and prolonged survival by whole-brain radiotherapy (WBRT) concomitant with intrathecal methotrexate (MTX). A literature review was included to summarize the present status of ER+ HER2− LM-BC. Discussion and Conclusions: There are a great number of studies on the therapy of LM from HER2+ BC, but there is limited information on ER+ HER2− BC with isolated LM, which is rarer than other BC subtypes and predicts a worse prognosis. Concurrent WBRT with intrathecal MTX may improve the quality of life and prolong the survival of LM-BC, especially for ER+ HER2− ones. Our case indicated ER+ HER2− LM-BC can be effectively treated by radiotherapy with concurrent intrathecal chemotherapy (IC). To provide longer and better survival benefits for patients with ER+ HER2− LM-BC, further trials are urgently needed to explore the therapeutic order and therapeutic dose of radiotherapy and intrathecal chemotherapy.