Abstract
Long-term cognitive effects following acute lymphoblastic leukemia treatment have been reported for Caucasians; however, these data remain unclear for other ethnicities and the treatment of other cancers. Here, we assessed cognitive function in Japanese childhood cancer survivors. This study enrolled 53 Japanese survivors of childhood cancer （mean age, 9.5 years; 36 boys and 17 girls）. We evaluated performance-based cognitive function using the Wechsler Intelligence Scale for Children-Fourth Edition （WISC-Ⅳ）. Deviation intelligence quotients （IQ） for verbal comprehension （VC）, perceptual reasoning （PR）, processing speed （PS）, and working memory （WM） were compared with the standardized mean and standard deviation （SD; 100 and 15, respectively）. We classified patients into three groups depending on the cumulative methotrexate （MTX） dose （none, 1–19g/m2, and＞20g/m2）. Full-scale IQ was within normal range at 104.8 （SD, 12.9）, although there were significant differences among the four WISC–Ⅳ index scores （P＜0.001）. The PS score （97.1±15.5） was significantly lower than the VC （107.2±15.8） and PR （105.3±14.2） scores （both P＜0.005）. WM performance decreased in an MTX dose-dependent manner （107.8, 102.6, and 96.5 for none, 1–19g/m2, and higher than 20g/m2, respectively; P=0.05）. Japanese childhood cancer survivors, including those in the non-MTX group, demonstrated significant PS impairment. High-dose MTX treatment might be associated with neurocognitive deficiencies, particularly in WM. Although current treatments are associated with high cure rates, future research and interventions are required to improve cognitive function in these patients.
