Background To evaluate the therapeutic benefits and side effects (especially leukoencephalopathy) of intrathecal methotrexate (MTX) in children aged over three years old with high-risk medulloblastoma (MB). Methods In the present retrospective study, patients who received intrathecal MTX during chemotherapy were classified as MTX group, while those receiving cerebrospinal fluid (CSF) cytology analysis only were recruited in control group. Results Among the 46 MB patients, 32 were classified in MTX group, whereas 14 in control group. For those 32 patients in MTX group, 27 (84.38%) had metastatic disease, 3 (9.38%) had diffuse anaplasia, and 3 (9.38%) had residual disease greater than 1.5 cm 2. Molecular subgroup classification was available in 28 (87.5%) patients. Of those 14 patients in control group, 8 (57.14%) had metastatic disease, 3 (27.27%) had diffuse anaplasia, and 6 (42.86%) had residual disease greater than 1.5 cm 2. Molecular subgroup classification was available in 6 (42.86%) patients. The 5-year progression-free survival (PFS) was 70.99% (95% CI, 58.22%-90.42%) and 5-year overall survival (OS) was 72.99% (95% CI, 60.41%-93.06%) for MTX group, while those were 41.67% (95% CI, 17.93%-66.92%) and 50% (95% CI, 27.88%-77.14%) for control group, separately. Among the 32 patients in MTX group, 6 (18.75%) with group 4 disease developed MTX-related acute leukoencephalopathy and one of them died. Conclusions Intrathecal MTX improves the 5-year PFS and OS for children with high-risk MB. However, intrathecal MTX is not recommended for patients with group 4 MB due to the high risk of acute leukoencephalopathy.

Background: The incidence of relapsed neuroblastoma (NB) in the central nervous system (CNS) is less than 20%. Here, we presented eleven cases with CNS relapsed NB to better understand the CNS relapsed NB. Methods: Medical records from NB patients between January 1st, 2010 and December 31st, 2017 were reviewed to examine those diagnosed with CNS relapsed NB. The following patient information was extracted, including age, gender, histological subtyping, tumor stage, risk group, biomarkers, chemotherapy regimen and dosage, surgery details, treatment outcomes and follow-up, clinical manifestations of CNS relapsed NB, treatment protocols for CNS relapsed NB, and patient outcomes (including the cause of death). Results: From January 1st, 2010 to December 31st, 2017, eleven NB patients were diagnosed with CNS relapse at our department. All the eleven patients were classified to have high risk disease. The median time from the completion of chemotherapy to CNS relapse was 5 months. Five patients did not receive any treatment for the relapsed disease and finally died of it. Curative treatments were tried in six patients. At last, two patients with isolated CNS relapsed NB survived. Conclusions: The median time from the completion of chemotherapy to CNS relapse is very short in the present retrospective study. It seems that patients with isolated CNS relapsed disease have better outcomes. We suggest the temozolomide-topotecan combination as an add-one backbone for further salvage treatment in children with CNS relapsed NB, even though this combination is not superior to others in terms of its efficacy.