EPID-05. Incidence of Glioma Varies Significantly by Global Region

Brain and other central nervous system (CNS) tumors are a significant source of global morbidity and mortality. Despite decades of epidemiological research, there are few known risk factors for these tumors. Incidence of brain tumors varies significantly by country region of the world, and by sex, ethnicity, and age within countries. The aim of this study was to generate up-to-date estimates of glioma incidence rates by global region with the aim of providing a framework for international risk factor research. Using data from the International Agency for Research on Cancer’s Cancer Incidence in Five Continents-XII (new diagnoses from 2013-2017 from 460 cancer registries across 65 countries) and the Central Brain Tumor Registry of the United States from 2013-2017 (~99% of new US diagnoses) we calculated the incidence rates per 100,000 person-years and 95% confidence intervals age-adjusted to the world standard population (AAIR). Incidence was estimated for glioma, astrocytoma, and oligodendroglioma by age group, sex, site, and histology. Countries were grouped based on World Bank regional definitions. Glioma incidence varied significantly by region. The highest rates of glioma were seen in the Oceania (AAIR=5.23, 95%CI=5.13-5.33), and Northern Europe (AAIR=5.06, 95%CI=5.00-5.12). Lowest incidence was reported in Southeast Asia (AAIR=0.96, 95%CI=0.90-1.02) and Sub-Saharan Africa (AAIR=1.05, 95%CI=0.94-1.18). Astrocytic tumors and Oligodendroglioma were highest in Oceania (AAIR = 4.01, 95% CI=3.93-4.10, AAIR = 0.54, 95% CI =0.51-0.58, respectfully) and lowest in Southeast Asia (AAIR = 0.66, 95% CI=0.61-0.71, AAIR = 0.08, 95% CI=0.06-0.12, respectfully). There continues to be significant global variation in the incidence of glioma despite improvements in data collection and imaging technology. While inequitable access to health care resources may exacerbate these differences, assessment of regional differences may provide evidence for future risk factor study and provide information for planning of global research initiatives.