Survival rates of children and young adolescents with CNS tumors improved in the Netherlands since 1990: A population-based study

Introduction: Survival of children with central nervous system (CNS) tumors varies largely between countries. For the Netherlands, detailed population-based estimation of incidence, survival, and mortality of pediatric CNS tumors are lacking but are needed to evaluate progress. Methods: All CNS tumors diagnosed in patients <18 years during 1990-2017 were selected from the Netherlands Cancer Registry. Other than pilocytic astrocytomas, nonmalignant tumors were included since 2000. Incidence and mortality trends were evaluated by average annual percentage change (AAPC). Changes over time in the five-year observed survival (5-year OS) were evaluated by Poisson regression models adjusted for follow-up time. Results: Between 1990 and 2017, 2057 children were diagnosed with a malignant CNS tumor and 885 with a pilocytic astrocytoma. During 2000-2017, 695 children were diagnosed with other nonmalignant CNS tumors. Incidence rates of malignant tumors remained stable, while pilocytic astrocytomas and other nonmalignant tumors increased by 2.0% and 2.4% per year, respectively. The 5-year OS rates improved for all groups; however, improvement for malignant tumors was not constant over time. The contribution of malignant tumors located at the optic nerve tumors was 1% in 2000-2009. However, shifting from pilocytic astrocytomas, increased to 6% in 2010-2017, impacting survival outcomes for malignant tumors. Conclusion: Survival rates of CNS tumors improved over time but were not accompanied by a decreasing mortality rate. The observed temporary survival deterioration for malignant tumors appears to be related to changes in diagnostics and registration practices. Whether differences in treatment regimens contribute to this temporary decline in survival needs to be verified.