Editorial comment: “Diffuse glioma, not otherwise specified: imaging-based risk stratification achieves histomolecular-level prognostication”

Excerpt

Adult-type diffuse gliomas are the most common tumors of the central nervous system. Depending on the subtype, survival rates range from over 80% for low-grade gliomas to less than 20% for high-grade gliomas [1]. Over the 2016 and 2021 revisions of the World Health Organization (WHO) classification, the molecular profile has become increasingly important because specific genetic changes have been found to have essential prognostic implications. Currently, the diagnosis of adult-type glioma involves more than the presence of isocitrate dehydrogenase (IDH) and 1p/19q codeletion. However, it is acknowledged that some centers may not have the ability to carry out genetic testing or fluorescence in situ hybridization (FISH). Therefore, NOS (not otherwise specified) suffix is reserved for cases where a diagnostic test cannot be performed, or the results are inconclusive [2]. Tumors with histological grades 2 or 3 are a mixture of tumor types with different prognoses: oligodendroglioma, IDH-mutant and 1p/19q-codeleted; astrocytoma, IDH-mutant; glioblastoma, IDH wildtype. Lower grade gliomas, NOS can include all of these; hence, clinicians are struggling to manage them. …