Long Term Brain Toxicity of Chemotherapy in Patients Treated for a Bone TumorDuring Childhood or Adolescence

Inclusion Criteria: For study OSE A and B * Patients treated for a bone sarcoma: Ewing or osteosarcoma * Age under 19 years at initial diagnosis * Treated in the Pediatric Oncology Department of Gustave For patients diagnosed between 01.01.2001 and 31.12.2010: patients alive in complete remission at least 5 years after diagnosis * Treated with at least one course of HDMTX for osteosarcoma * Treated without HDMTX for Ewing sarcoma * Time interval between the end of treatment and inclusion \>10 y * Age \> 21 y at inclusion * Patients with informed consent signed * Patient under guardianship * Affiliated to French health insurance or beneficiary of the same or equivalent For study OSE- B only: * Treated with at least 8 courses of HDMTX for osteosarcoma * Treated without HDMTX for Ewing sarcoma * Patients with Ewing sarcoma will have to be matched with osteosarcoma patients according to age at the time of treatment, sex, and duration of follow-up * School level equivalent of at least the end of primary school Exclusion Criteria: For study OSE A and B * Brain radiotherapy * Previous relapse except those treated by local treatment without any chemotherapy * Second malignancy treated with chemotherapy * High dose chemotherapy with stem cell support * Non-French speaking patients * Pregnant and breastfeeding women For study OSE- B only: \- Patient deprived of his liberty by a judicial or administrative decision