Worldwide trends in survival from adult glioma 2000-2014 (CONCORD-3): Impact of morphology

Abstract

Background: The CONCORD programme initiated world-wide surveillance of trends in population-based cancer survival in 2015. The third cycle (CONCORD-3) covered 18 cancers, including brain tumours. Data for 656,659 adults (15-99 years) diagnosed with a brain tumour were provided by 286 registries in 59 countries. For adults diagnosed during 2010-2014, 5-year net survival from all brain tumours combined varied between 15% and 42%. We will present detailed comparison of survival trends for gliomas defined by anatomic location, morphology andWHOgrade. Methods: We will present the numbers of adults diagnosed with a glioma and the subtype distribution by continent. We will estimate net survival up to 5 years, using the unbiased Pohar Perme estimator. Net survival is the probability that patients survive their cancer until a given time since diagnosis, after controlling for competing risks of death (background mortality) by age, sex, country and calendar year. Results: Data were obtained for 545,184 adults. Glioblastoma was the most common morphology (57%). Astrocytic, oligodendroglial and oligo-astrocytic tumours specified asWHOgrade I-III made up 21% of all gliomas, while glioma not otherwise specified (NOS) and astrocytoma NOS made up 15%. Rarer tumours, such as oligodendroglioma, fibrillary astrocytoma, pilocytic astrocytoma, mixed glioma, anaplastic oligodendroglioma and anaplastic astrocytoma made up less than 10% of gliomas in all continents. The frequency of glioblastoma was 58% or higher in Europe, North America and Oceania, 53% in Africa and around 45% in Asia and Central and South America. The frequency of astrocytoma NOS was lowest in Europe, North America and Oceania (below 9%) and highest in Central and South America (22%). Conclusions: The distribution of gliomas varies around the world. The differential was the frequency of unspecified morphologies, which may be partly attributable to diagnostic capacity. We will assess the extent to which disparities in morphology contribute to worldwide variation in survival from adult brain tumours. When comprehensive survival analyses are available, this project is expected to become the reference for international comparison of brain tumour survival, to help inform national cancer control plans.