Radboud University Nijmegen - Department of Hematology, Princess Máxima Center for Pediatric Oncology, Radboud University Nijmegen - Department of Hematology, University of Twente - Department of Health Technology & Services Research, Radboud University Nijmegen - Department of Hematology, Lund University - Division of Oncology and Pathology, Danish Cancer Society Research Centre - Childhood Cancer Research Group, Lund University - Division of Pediatrics, Masaryk University - International Clinical Research Centre (FNUSA-ICRC), Masaryk University - International Clinical Research Centre (FNUSA-ICRC), Princess Máxima Center for Pediatric Oncology, IRCCS Istituto Giannina Gaslini - DOPO Clinic, Princess Máxima Center for Pediatric Oncology, Childhood Cancer International - Europe, KU Leuven - Department of Oncology, University of Newcastle - Wolfson Childhood Cancer Research Centre, KU Leuven - Department of Oncology, University of Newcastle - Wolfson Childhood Cancer Research Centre, Radboud University Nijmegen - Scientific Institute for Quality of Healthcare (IQ Healthcare) and Radboud University Nijmegen - Department of Hematology