1. Department of Pediatric Oncology, IHOP; Centre Léon Bérard; Lyon France
2. Aix-Marseille University and Pediatric Department of APHM; Marseille France
3. Department of Statistics; Centre Léon Bérard; Lyon France
4. Department of Pediatric Oncology; Institut Curie; Paris France
5. Department of Pediatric; CHU de Rennes; Rennes France
6. Department of Pediatric; Bordeaux, CHU; France
7. Department of Pediatric Oncology; Gustave Roussy; Villejuif France