1. Medical Department, Brussels, Belgium
2. Statistics Department, Brussels, Belgium
3. European Organisation for Research and Treatment of Cancer HQ, Brussels, Belgium
4. Pediatric Oncology Department, Hospital Donostia, San Sebastian, Spain
5. Clinical Research Unit, Hospital Niño Jesús, Madrid, Spain
6. Department of Oncology for Child and Adolescent, Gustave Roussy Cancer Campus, Villejuif, France
7. Medical Oncology Department, Institut de Cancérologie des Hospices Civils de Lyon, Université Lyon 1, Lyon, France