Brief report: effect of intravenous methotrexate dose and infusion rate on neuropsychological function one year after diagnosis of acute lymphoblastic leukemia

OBJECTIVE: To compare the effects of two intravenous (IV) methotrexate (MTX) infusion protocols on cognitive function in children newly diagnosed with acute lymphoblastic leukemia (ALL). METHODS: We compared 19 children treated with 1 g/m(2) of IV MTX over 24 hr (Group 1) to 13 children treated with 2 g/m(2) of IV MTX over 4 hr (Group 2) on measures of working memory, nonverbal, and verbal skills shortly after diagnosis (Time 1) and 1 year later (Time 2). RESULTS: A significant GroupxTime interaction was found for a composite measure of working memory with Group 2 declining from Time 1 to Time 2. Group 2 performed significantly worse than Group 1 on a composite measure of nonverbal skills at both time points. CONCLUSIONS: Findings suggest that difficulties in working memory and nonverbal skills may be evident during the first year of treatment for ALL and that severity may be dependent on IV MTX dose and/or infusion rate.