High-dose intravenous methotrexate for patients with nonleukemic leptomeningeal cancer: Is intrathecal chemotherapy necessary?

Purpose: Standard treatments for neoplastic meningitis are only modestly effective and are associated with significant morbidity, Isolated reports suggest that concurrent systemic and intrathecal (IT) therapy may be more effective than IT therapy alone. We present our experience, which includes CSF and serum pharmacokinetic data, on the use of high-dose (HD) intravenous (IV) methotrexate (MTX) as the sole treatment for neoplastic meningitis. Patients and Methods: Sixteen patients with solid-tumor neoplastic meningitis received one to four courses (mean, 2.3 courses) of HD (8 g/m(2) over 4 hours) IV MTX and leucovorin rescue. Serum and CSF MTX concentrations were measured daily. Toxicity, response, and survival were retrospectively compared with a reference group of 15 patients treated with standard IT MTX during the same time interval. Results: Peak methotrexate concentrations ranged from 3.7 to 55 mu mol/L (mean, 17.1 mu mol/L) in CSF and 178 to 1,700 mu mol/L (mean, 779 mu mol/L) in serum, Cytotoxic CSF and serum MTX concentrations were maintained much longer than with IT dosing. Toxicity was minimal, Cytologic clearing was seen in 81% of patients compared with 60% of patients treated intrathecally (P = .3). Median survival in the HD IV MTX group was 13.8 months versus 2.3 months in the IT MTX group (P = .003). Conclusion: HD IV MTX is easily administered and well tolerated. This regimen achieves prolonged cytotoxic serum MTX concentrations and CSF concentrations at least comparable to those achieved with standard IT therapy. Cytologic clearing and survival may be superior in patients treated with HD IV MTX. Prospective studies and a reconsideration of the use of IT chemotherapy for patients with neoplastic meningitis are warranted. (C) 1998 by American Society of Clinical Oncology.