Epidemiology of glioma: clinical characteristics, symptoms, and predictors of glioma patients grade I–IV in the the Danish Neuro-Oncology Registry

In this national population-based study of glioma, we present epidemiologic data on incidence, demographics, survival, clinical characteristics and symptoms, and evaluate the association of specific indicators with the grade of glioma. We included 1930 patients registered in the Danish Neuro-Oncology Registry (DNOR) from 2009 to 2014. DNOR is a large-scale national population-based database including all adult glioma patients in Denmark. The age-adjusted annual incidence of histologic verified glioma was 7.3 cases pr. 100,000 person-years. High-grade gliomas were present in 85% and low-grade glioma in 15%. The overall male:female ratio was 3:2 and the mean age at onset was 60 years. Data for WHO grade I, II, III and IV glioma showed several important differences regarding age and sex distribution and symptomatology at presentation. The mean age increased with the grade of glioma and males predominated in all grades. Focal deficits were the most frequent presenting symptom, but among patients with glioma, grade II epileptic seizures were the most frequent symptom. Headache was a rare mono-symptomatic onset symptom. At presentation, higher age, focal deficits and cognitive change for <3 months duration, and headache <1 month were significant independent indicators of high-grade gliomas. Younger age and epileptic seizures for more than 3 months were indicative for low-grade gliomas. Survival rates for glioma grade I–IV showed decreasing survival with increasing grade. Glioma grade I–IV showed high diversity regarding several demographic and clinical characteristics emphasizing the importance of individually tailored disease treatments and support.