Challenges in determining the global burden of non-malignant central nervous system tumors: an analysis of international incidence and mortality data sources.

BACKGROUND: Non-malignant tumors of the CNS contribute substantially to the morbidity and mortality from CNS tumors. It is critical to understand the epidemiology of non-malignant CNS tumors separately from CNS malignancies to inform resource allocation and policy since treatment and prognosis can differ. High quality international data on non-malignant CNS tumor burden are needed to accomplish this goal. METHODS: We assessed cancer registry and vital registration data available to the Global Burden of Disease study by its inclusion of non-malignant CNS tumors, reporting on the availability of data over time and by World Bank income group. We analyzed preliminary age-standardized incidence rates (ASIRs), age-standardized mortality rates (ASMRs), and proportions of CNS tumors by behavior for adults, children, and all ages. RESULTS: Non-malignant CNS tumors were reported separately in 17·2% (N=66) of registry reports and in aggregate with malignant CNS tumors in 18·0% (N=69) of reports. Only seven low- and middle-income countries (LMICs) had data reporting CNS tumors separately by behavior. Across all ages combined, the median ASIR of non-malignant CNS tumor data was 0·31 (interquartile range: 0·15-0·50) and ASMR was 0·24 (0·10-0·44) per 100,000 in LMICs compared to median ASIR of 3·62 (2·62-4·97) and ASMR of 0·32 (0·16-0·65) in high-income countries (HICs). A larger proportion of incident CNS tumors across were reported as non-malignant in HIC data than LMIC data (p<0.0001). CONCLUSIONS: Our study alludes to current challenges in understanding global non-malignant CNS tumor burden and a need for increased international data collection. Further research is needed to comprehensively investigate opportunities for future data inclusion.