1. From the Unit for Pediatric Oncology and Hematology, Department of Women's and Children's Health, Uppsala University Children's Hospital, Uppsala, Sweden;
2. Department of Pediatric Anesthesia and Intensive Care, Sahlgrenska University Hospital, Sahlgrenska, Sweden;
3. Multidisciplinary Center for Pain Treatment, Department of Anesthesiology and Intensive Care, University Hospital, Uppsala, Sweden; and the
4. Department of Research, Central Hospital, Västerås, Sweden.