Background: The incidence rates of childhood central nervous system (CNS) tumors in the Nordic countries remain among the highest in the world. Large geographical and temporal variations in the incidence rates of CNS tumors have been reported. Increasing incidence rates would be a public health concern, as they might indicate increased exposure to environmental risk factors.
Methods: All 3,983 children 0-14 years of age registered with a primary CNS tumor in 1985-2006 in the national cancer registries of the Denmark, Finland, Norway, and Sweden were identified. Tumors were classified according to the International Classification of Childhood Cancer version 3 (ICCC-3). Join-point analysis was used to detect changes in trends and to estimate annual changes in incidence rates.
Results: The mean annual incidence rate of CNS tumors was 42 per million. No statistically significant change in time trends of incidence rates was observed during 1985-2006. Furthermore, the incidence by birth cohort was relatively stable during the study period.
Conclusion: The incidence rates of childhood CNS tumors in the Nordic countries remain among the highest in the world. The stable incidence rates during the last 22 years indicate that major changes in environmental risk factors are unlikely.