2021 Volume 58 Issue 5 Pages 424-431
High-dose intravenous methotrexate (HD-MTX) and intrathecal MTX can cause long-term neurotoxicity that adversely affects intellectual function. We report the final results of a three-year longitudinal study of cognitive function of patients from 23 institutions. Data were collected from children diagnosed as having standard-risk acute lymphoblastic leukemia (ALL) between 2011 and 2016. A total of 57 patients aged three to nine years at the time of diagnosis were consecutively enrolled and the results of 43 were statistically analyzed. We used the Wechsler Intelligence Scale for Children-4th Edition (WISC-IV) to obtain the scores for full-scale IQ (FSIQ), verbal comprehension index (VCI), perceptual reasoning index (PRI), working memory index (WMI), and processing speed index (PSI). The cognitive function of participants was tested using WISC-IV before and three times after the completion of HD-MTX therapy over three years. The four indices (VCI, PRI, WMI, and PSI) were statistically compared across four time points using ANOVA. Mean FSIQ scores were 99.09 (SD=14.72), 99.26 (SD=15.01), 102.30 (SD=11.08), and 101.12 (SD=11.69) at the four time points, respectively. Scores of Verbal Comprehension at TIME 1 were the lowest, whereas those of Working Memory were the lowest after TIME 2. These results should be verified with respect to daily life problems encountered by the patients.