1. Pediatrics 1 Olgahospital, Klinikum Stuttgart Stuttgart Germany
2. Pediatrics 5 Olgahospital, Klinikum Stuttgart Stuttgart Germany
3. Department of Pediatrics St. Anna Children's HospitalMedical University Vienna Vienna Austria
4. German Childhood Cancer Registry, Institute for Medical Biostatistics, Epidemiology and Informatics University Medical Center of the Johannes Gutenberg‐University Mainz Mainz Germany
5. University Children's Hospital Basel Basel Switzerland
6. Cooperative Ewing Sarcoma Study Group Essen University Hospital Essen Germany
7. Division of Pediatric Hematology and Oncology Hospital for Children and Adolescents Johann Wolfgang Goethe University Frankfurt Germany
8. University of Tuebingen Tuebingen Germany
9. Institute of Biostatistics and Clinical Research University of Münster Münster Germany