A retrospective case series of 103 consecutive patients with leptomeningeal metastasis and breast cancer.

Approximately 2-5 % of patients with breast cancer (BC) develop leptomeningeal metastasis (LM). 103 consecutive patients with BC were diagnosed with LM and initially treated with intra-CSF liposomal cytarabine from 2007 to 2011 at a single institution. Correlations were determined with respect to patient characteristics and BC subtype with regard to overall survival (OS). At LM diagnosis, 61 % of patients had a 0-2 performance status (PS), the remaining 39 % were severely neurologically impaired. Regardless of PS, all patients received intra-cerebrospinal fluid (CSF) liposomal cytarabine as first-line treatment. Systemic treatment and radiotherapy were also given in 58 and 17 % of patients respectively as clinically appropriate. Second- (intra-CSF thiotepa) and third-line (intra-CSF methotrexate) treatment was administered in 24 and 6 patients respectively. Median OS was 3.8 months (range 1 day-2.8 years). In multivariate analysis, an initial combined treatment, a second-line treatment with intra-CSF thiotepa, an initial clinical response, and a non-'ER/PR/HER2 negative' BC were significantly associated with a better OS. Median OS in this heterogeneous retrospective case series was similar to that of previously observed BC patients treated with intra-CSF methotrexate suggesting intra-CSF liposomal cytarabine is a reasonable first choice therapy of BC-related LM.