Demographic and clinical characteristics of patients with metastatic breast cancer and leptomeningeal disease: a single center retrospective cohort study

Purpose Leptomeningeal disease (LMD) is a devastating complication of metastatic breast cancer (MBC). It is critical to better understand the risk factors, natural history, and treatment outcomes, including patients in a modern cohort. Methods In this single center retrospective cohort study, we identified patients with MBC and LMD who received care from 2000 to 2024 and abstracted key clinical, treatment, and survival data. Results We identified 111 patients with MBC and LMD, including patients with the following subtypes: HR+/HER2− ( n = 53, 47.7%), HER2+ ( n = 30, 27.0%), and triple negative breast cancer (TNBC; n = 28, 25.2%). Median time from the diagnosis of MBC to LMD was 16.4 months (range 0–101.3 months). After the diagnosis of LMD, most patients received systemic therapy ( n = 66, 59.5%) and/or central nervous system (CNS)-directed therapy ( n = 94, 84.7%) including intrathecal therapy ( n = 42, 37.8%) and/or CNS-directed radiation therapy ( n = 70, 63.1%). In all patients, median overall survival (OS) from the diagnosis of LMD to death was 4.1 months (range 0.1–78.1 months) and varied by subtype, with HR+/HER2− or HER2+ MBC patients living longer than those with TNBC (4.2 and 6.8 months respectively vs. 2.0 months, p