Concurrent intrathecal methotrexate and liposomal cytarabine for the treatment of leptomeningeal metastasis from solid tumors.

2052 Background: Leptomeningeal metastasis (LM) from solid tumors is typically a late manifestation of disease with a median survival of weeks to a few months. Treatment is palliative, with no widely accepted standard of care. Options include intrathecal (IT) or systemic chemotherapy, radiation therapy or ventriculoperitoneal shunting. Randomized trials comparing single agent IT methotrexate to liposomal cytarabine have shown similar efficacy and tolerability. There is limited data, however, on the use of combination IT chemotherapy in solid tumor LM. Methods: We conducted a retrospective cohort study of 19 subjects treated for LM from solid tumors at a single institution. In addition to therapies directed at active solid tumor sites, each subject received IT liposomal cytarabine plus IT methotrexate injections every two weeks. Survival data and treatment-related toxicities were determined by systematic chart review. Results: LM was diagnosed by CSF cytology in 12/19 (63%), while the remainder were diagno...