Forty years of follow-up: Incidence, diagnoses and long-term survival in children diagnosed with central nervous system tumors in Sweden 1984-2021

Abstract Background Central nervous system (CNS) tumors are the second most common childhood malignancy and a leading cause of cancer-related mortality. This national population-based study describes childhood primary CNS tumors diagnosed in Sweden over 40 years, incorporating the latest WHO classification and long-term survival data. Methods All primary CNS tumors in children (0-14 years), diagnosed between 1984 and 2021 and registered in Swedish Cancer Registries, were reviewed. Data on tumor location, histology, and the reclassified supratentorial CNS-PNETs were incorporated. Tumors were categorized according to the International Classification of Childhood Cancer, third edition. Incidence and survival rates were analyzed. Results Overall, 2954 children (<15 years) were diagnosed with a CNS tumor in Sweden 1984-2021. The average incidence rate was 4.6/100 000 children per year, and it remained stable during the study period. Astrocytomas constituted 49%, embryonal tumors 17%, and ependymomas 7% of cases. Five-year overall survival improved from 75% to 82% over the study period. However, several tumor types showed a continued decline in survival at 30 years of follow-up. Conclusions This 40-year population-based study provides comprehensive data on childhood CNS tumors in Sweden. The incidence remained stable during the 4 decades. The distribution of tumor diagnoses is in line with other countries. Survival has improved over time, but for some diagnoses, late mortality is seen many years after primary diagnosis, highlighting the importance of long-term follow-up.