IRRADIATION, METHOTREXATE TOXICITY, AND THE TREATMENT OF MENINGEAL LEUKÆMIA

Abstract 31 patients with meningeal leukaemia were randomised to therapy with intrathecal methotrexate with and without 2400r to the cranial vault. Remissions were achieved in 29 patients. Remission duration was significantly longer (234 + days) in the group receiving methotrexate alone than in those receiving methotrexate and irradiation (125 days). A spectrum of methotrexate toxicity was seen after intrathecal administration ranging in severity from chemical arachnoiditis which was common (17 patients) through transient paresis (1 patient) to encephalopathy (2 patients). These toxicities were just as common in patients receiving preservative-free methotrexate as in those receiving methotrexate with preservative, and therefore should be ascribed to direct toxic effects of methotrexate itself or its breakdown products rather than preservative. The neurotoxicity of methotrexate must be taken into account in evaluating the risks and benefits of the therapy for meningeal leukaemia.