Paediatric and adolescent medulloblastoma and CNS-PNET in Norway 1974 – 2013: Survival, regional differences, and late effects

Abstract

Medulloblastoma (MB) and supratentorial primitive neuroectodermal tumor (CNS-PNET) are embryonal brain tumours, and they account for about 15%–20% and 2.5%, respectively, of malignant brain tumors in children and adolescents. The aim of the thesis was two-fold. First, to investigate whether there within Norway were re-gional differences in survival for patients with MB and CNS-PNET in the time period 1974–2013, and if so try and identify possible explanations for such differences. The second aim was to determine frequency and severity of undesirable late effects in MB and CNS-PNET survivors, and evaluate rehabilitation need. We performed a retrospective study of patients diagnosed with MB or CNS-PNET in Norway between 1974 and 2013. Second, a clinical follow-up study focusing on late effects and rehabilitation need for MB and CNS-PNET survivors in South-Eastern Norway Regional Health Authority was performed. At the time of analysis, 46% of all Norwegian patients were alive. In univariable analysis, five-year OS, but not five-year event-free survival (EFS), for MB/CNS-PNET altogether was significantly better at University Hospital Of North Norway, St. Olavs Hospi-tal Trondheim University Hospital, and Haukeland University Hospital, compared to Oslo University Hospital (68% vs 54%). We were not able to identify any possible explanations for these regional survival differences within Norway. In the clinical follow-up study, a high burden of unwanted late effects was found in paediatric, adolescent, and adult MB and CNS-PNET survivors, in the vast majority of cases leading to unmet rehabilitation needs. It is im-portant to note that several late effects do not occur until years or even decades following completion of anti-neoplastic treatment and these patients will therefore need life-long follow-up and rehabilitation.