World Health Organization 2021 Classification of Central Nervous System Tumors and Implications for Therapy for Adult-Type Gliomas

Abstract

ImportancePrevious histologic classifications of brain tumors have been limited by discrepancies in diagnoses reported by neuropathologists and variability in outcomes and response to therapies. Such diagnostic discrepancies have impaired clinicians’ ability to select the most appropriate therapies for patients and have allowed heterogeneous populations of patients to be enrolled in clinical trials, hindering the development of more effective therapies. In adult-type diffuse gliomas, histologic classification has a particularly important effect on clinical care.ObservationsIn 2021, the World Health Organization published the fifth edition of the Classification of Tumors of the Central Nervous System. This classification incorporates advances in understanding the molecular pathogenesis of brain tumors with histopathology in order to group tumors into more biologically and molecularly defined entities. As such, tumor classification is significantly improved through better characterized natural histories. These changes have particularly important implications for gliomas. For the first time, adult- and pediatric-type gliomas are classified separately on the basis of differences in molecular pathogenesis and prognosis. Furthermore, the previous broad category of adult-type diffuse gliomas has been consolidated into 3 types: astrocytoma, isocitrate dehydrogenase (IDH) mutant; oligodendroglioma, IDH mutant and 1p/19q codeleted; and glioblastoma, IDH wild type. These major changes are driven by IDH mutation status and include the restriction of the diagnosis of glioblastoma to tumors that are IDH wild type; the reclassification of tumors previously diagnosed as IDH-mutated glioblastomas as astrocytomas IDH mutated, grade 4; and the requirement for the presence of IDH mutations to classify tumors as astrocytomas or oligodendrogliomas.Conclusions and RelevanceThe 2021 World Health Organization central nervous system tumor classification is a major advance toward improving the diagnosis of brain tumors. It will provide clinicians with more accurate guidance on prognosis and optimal therapy for patients and ensure that more homogenous patient populations are enrolled in clinical trials, potentially facilitating the development of more effective therapies.

ALDH1-Mediated Autophagy Sensitizes Glioblastoma Cells to Ferroptosis

“…Glioblastoma specimens (IDH wildtype, CNS WHO grade 4 according to the WHO classification of tumors of the central nervous system [ 11 ]) were collected from the Department of Neurosurgery, Klinikum rechts der Isar of Technical University of Munich with patients’ informed consent. Collection and use of patient-derived tumor samples were approved by the regional ethics committee.…”

Benefits of supportive strategies for carers of people with high-grade glioma: a systematic review

“…Two authors (DJ and RJ) independently conducted title, abstract, and full-text screening in duplicate, with disagreements resolved by consensus. Inclusion criteria included [1] adult (> 18 years) carers of adults with HGG, whereby carers were defined as the principal unpaid, informal caregiver; [2] any supportive strategy involving carer participation which reported quantitative and/or qualitative carer data, implemented at any stage of the disease trajectory; [3] described or evaluated any intervention, programme, or service that addressed any carer needs including psychological/emotional needs, information, health service needs, and work/social needs [29]; and [4] included studies of any design published in peer-reviewed journals and written in English. Studies of carers for people with glioma were narratively synthesised under categories of supportive strategies.…”

“…High-grade glioma (HGG), defined as grade 3 and grade 4 glioma by the World Health Organisation (WHO) [2], is most common in adults and is often characterised by the rapid onset and progression of physical and neurological symptoms [3]. Even with standard-of-care treatment comprising surgery followed by radiotherapy and chemotherapy, patients with glioblastoma (WHO grade 4 glioma) have a median overall survival of 12-23 months [4]. Most people with HGG are managed in the outpatient setting, therefore their spouse or other family members usually accept primary responsibility for care [5].…”

Recent Developments in Glioblastoma Therapy: Oncolytic Viruses and Emerging Future Strategies

“…These grades indicate a different degree of malignancy and help to select the proper treatment for each case [ 4 ]. In 2021, WHO updated its classification of central nervous system (CNS) tumors in which genetic features and molecular patterns alongside histopathological ones are used in designating different kinds of gliomas [ 1 , 5 ]. Glioblastoma is recognized as an IDH-wildtype diffuse glioma and the “IDH-mutant glioblastoma” term was eliminated [ 5 ].…”

“…In 2021, WHO updated its classification of central nervous system (CNS) tumors in which genetic features and molecular patterns alongside histopathological ones are used in designating different kinds of gliomas [ 1 , 5 ]. Glioblastoma is recognized as an IDH-wildtype diffuse glioma and the “IDH-mutant glioblastoma” term was eliminated [ 5 ]. This review uses the abbreviation “GB” to indicate glioblastoma instead of “GBM”, originally used for glioblastoma multiforme.…”