Impact of epidemiological characteristics of supratentorial gliomas in adults brought about by the 2016 world health organization classification of tumors of the central nervous system

Abstract

The latest World Health Organization (WHO) classification of tumors of the central nervous system (CNS) integrates both histological and molecular features in the definition of diagnostic entities. This new approach enrolls novel entities of gliomas. In this study, we aimed to reveal the epidemiological characteristics, including age at diagnosis, gender ratio, tumor distribution and survival, of these new entities. We retrospectively reclassified 1210 glioma samples according to the 2016 CNS WHO diagnostic criteria. In our cohort, glioblastoma multiforme (GBM) with wildtype isocitrate dehydrogenase (IDH) was the most common malignant tumor in the brain. Almost all gliomas were more prevalent in males, especially in the cluster of WHO grade III gliomas and IDH-wildtype GBM. Age at diagnosis was directly proportional to tumor grade. With respect to the distribution by histology, we found that gliomas concurrent with IDH-mutant and 1p/19q-codeleted or with single IDH-mutant were mainly distributed in frontal lobe, while those with IDH-wildtype were dominant in temporal lobe. Lesions located in insular lobe were more likely to be IDH-mutant astrocytoma. In summary, our results elucidated the epidemiological characteristics as well as the regional constituents of these new gliomas entities, which could bring insights into tumorigenesis and personalized treatment of Chinese glioma population.

NCCN Guidelines Insights: Central Nervous System Cancers, Version 1.2017

“…[2][3][4][5][6] • Molecular characterization of primary brain tumors/gliomas has had a substantial impact on stratifi cation and eligibility in clinical trials for CNS neoplasms over the last 10 years, and is increasingly becoming a common part of standard neuro-oncology management.…”

“…In the 2007 WHO system, grade II and III gliomas were further categorized based on cell types; the most commonly observed histologic subtypes are astrocytoma, oligodendroglioma, and oligoastrocytoma. 3 Although the 2007 WHO system of grading and subtyping based on histology has been shown to provide some prognostic separation (for overall survival [OS] and progression-free survival [PFS]) in a few studies of larger populations (≥300 patients) with brain tumors, 4,5 results from other studies are less convincing and more variable. [6][7][8][9][10][11][12][13] shown to be limited by interobserver variability, especially for certain categories.…”

“…5,9,27,29 Remarkably, further analysis showed that these molecular subgroups could be distinguished based on only a handful of molecular features, including mutation of IDH1 or IDH2 (IDH-mut) and 1p19q-codel, biomarkers independently verified by many studies as hallmarks for distinguishing molecular subgroups in grade II/III glioma. [4][5][6][7]9,13,28,[30][31][32][33][34][35][36][37][38][39] Using these markers alone, most grade II/III tumors can be divided into 3 molecular subtypes: (1) mutation of either IDH1 or IDH2 with 1p19q codeleted (IDH-mut+1p19q-codel), (2) IDH-mut without deletion of 1p or 19q (1p19q intact) or with isolated deletion of 1p or 19q, and (3) no mutation of IDH1 or IDH2 (IDH-wt). 5 Multiple studies have shown that codeletion of 1p and 19q is strongly associated with IDH-mut, such that 1p19q codeletion in IDH-wt tumors is rare.…”

“…Numerous large studies of patients with brain tumors have shown that among grade II/III gliomas, 1p19q-codel is significantly correlated with improved PFS and OS. 4,6,7,9,10,13,30,32,41,42 Many of these studies used heterogenous populations treated with a variety of approaches, but a few showed statistically significant correlation between 1p19q-codel and outcome within a population of patients who received the same treatment. The independent prognostic value of 1p19q status was also confirmed through multivariate analyses from multiple studies in patients with grade II/III glioma.…”

“…The independent prognostic value of 1p19q status was also confirmed through multivariate analyses from multiple studies in patients with grade II/III glioma. 4,7,13,41,42 For IDH mutation status, although a few analyses did not find a significant correlation with PFS, 7,32 many more studies found that IDH-mut was associated with improved PFS, including several multivariate analyses. 4,9,10,42,43 Numerous large studies, including many multivariate analyses, all found that IDH-mut is significantly associated with improved OS in patients with grade II/III glioma.…”