Patients
This study was approved by the Ethical Institution of our hospital. Medical records from patients aged over 3 years with high-risk MB between January 1st, 2010 and December 31st, 2018, were reviewed. High-risk MB was defined as residual disease >1.5 cm2, diffuse anaplasia histology and metastatic spread of disease (M0,1,2,3) according to the Chang’s classification[6]. Patients receiving intrathecal MTX were classified into MTX group, while those without intrathecal MTX into control group. Patients in WNT subgroup were excluded due to the good previous treatment response.
The following data were extracted from each patient, including age, gender, histological subtype, tumor stage, risk group, molecular subgroup, chemotherapy regimen and dosage, details of MTX intracranial injection, clinical manifestation of leukoencephalopathy, treatment regimen of leukoencephalopathy, and patient outcomes (including the cause of death). Data collection from clinical records of patients was approved by the Institutional Review Boards. All data were anonymous, and informed consent was waived due to the retrospective observational nature of this study. Additionally, written informed consents were obtained from the parents or legal guardians of patients before the initiation of chemotherapy.