Incidence and survival for childhood central nervous system tumours in Australia, 1983–2016

Purpose: To investigate incidence and survival of childhood tumours of the central nervous system (CNS) by histological subtype, tumour behaviour and tumour grade. Methods: National, population-based data on all children under 15 years old diagnosed with a CNS tumour between 1983 and 2016 were sourced from the Australian Childhood Cancer Registry. Incidence rate trends were calculated using Joinpoint regression. Relative survival was calculated using the cohort method, with changes in survival over time by cancer type and tumour grade assessed by multivariable flexible parametric survival modelling. Results: The study cohort included 4914 patients, with astrocytoma (n = 2181, 44%) and embryonal tumours (n = 931, 19%) the most common diagnostic subgroups. Almost half (n = 2181, 44%) of all tumours were classified as high grade (III or IV). Incidence rates increased by 29% between 1983 and 2016, with high grade tumours rising by an annual average of + 1.1% (95% CI = + 0.7%, + 1.5%, p < 0.001). 5-year survival for all patients combined was 72% (95% CI = 71–74%), ranging from 50% (46–54%) for those with other gliomas to 81% (79–83%) for astrocytoma (p < 0.001). Survival improved over time for grade II and III ependymomas but not for patients with astrocytoma irrespective of grade. Conclusion: Improvements in diagnostic technology leading to more precise tumour classification are likely to explain some of the differences in incidence rate trends by histological type and grade. While improvements in survival over time were noted for some tumours, outcomes remained poor among patients with high-grade astrocytoma.