Regional and socio-economic variation in survival after glioblastoma in Denmark, 2013-2018

INTRODUCTION. Glioblastoma is the most frequent primary brain tumour in adults. In Denmark, the treatment of glioblastoma is centralised to four neurosurgical and oncological departments located in four of the five Danish administrative regions. The aim of this study was to examine the regional and socioeconomic variation in survival after a diagnosis of glioblastoma in Denmark. METHODS. We included 1,731 patients with histologically confirmed glioblastoma from 2013 to 2018 registered in the Danish Neuro-oncology Registry. The data sources were the Danish National Registries. The exposure was region of residence at diagnosis and household income in the year before diagnosis. Follow-up was initiated at diagnosis and concluded at death or end-of-follow-up on 15 July 2019. Cox regression was used to examine overall mortality by exposure. RESULTS. With adjustment for age, sex, year of diagnosis and comorbidity, mortality rates of glioblastoma patients varied significantly between regions and were lowest in the Region of Southern Denmark and highest in the Capital Region (hazard ratio = 0.79; 95% confidence interval: 0.68-0.91, compared with the Capital Region). Further adjustment for surgical resection attenuated the regional differences in mortality. Income was not a predictor of survival. CONCLUSIONS. We found significant regional variation in survival after a diagnosis of glioblastoma. Differences in treatment patterns between regions may explain part of this mortality variation. Household income and education level did not explain the regional differences. FUNDING. none. TRIAL REGISTRATION. not relevant.