Leptomeningeal metastases from breast cancer: intrinsic subtypes may affect unique clinical manifestations.

Leptomeningeal metastasis (LM) usually occurs late during the course of breast cancer. The aim of this study was to characterize the clinical features and outcomes of LM based on breast cancer subtypes in conjunction with brain parenchymal metastases. A retrospective study was performed of breast cancer patients with LM, who received palliative management at Samsung Medical Center between 1995 and 2008. Among the 272 metastatic breast cancer patients with central nervous system (CNS) involvement, 68 patients with LM were identified. The median age was 46 years (range, 24-72 years). The median survival duration from LM to death (LM-OS) was 4.5 months (range, 0.2-26.4 months). Patients surviving for 12 or more months were rarer among triple negative (TN) patients compared to other subtypes (21.7% for HR + ve vs. 27.8% for HER2 + ve vs. 72.7% for TN, P = 0.217). Death caused by CNS involvement appeared to be much more common in TN than in other subtypes (0% for HR + ve vs. 36% for HER2 + ve vs. 64% for TN, P = 0.060). Median survival time from distant metastasis was significantly different among the three groups (28.3 vs. 29.1 vs. 11.8 months, P < 0.0001). However, median survival time from LM did not differ (4.1 vs. 5.9 vs. 3.8 months, P = 0.226). Characteristic manifestations and treatment outcomes of LM may be affected by the unique biology of breast cancer intrinsic subtypes. The different roles of active combined treatment modalities including both systemic chemotherapy and local treatment modalities should be considered to improve outcomes.