Histopathological grading affects survival in patients with isocitrate dehydrogenase-wildtype gliomas

Background The World Health Organization (WHO) Classification of Tumors of the Central Nervous System (2021) defines lower-grade (WHO grade II/III) isocitrate dehydrogenase (IDH) wild-type astrocytoma as glioblastoma, IDH-wildtype, WHO grade 4. However, this definition is conditional. Notably, the traditional histopathological grade is no longer used, and the independent prognostic factor of tumor grade in IDH wild-type gliomas remains unclear. In this study, we aimed to determine if histopathological grade is an independent prognostic factor. Methods The clinical data and pathological information of 647 patients with IDH wild-type gliomas from the Chinese Glioma Genome Atlas (CGGA) database (2006-2019) were retrospectively analyzed. All patients were stratified according to histopathological grade and its prognostic significance in IDH wild-type gliomas. Univariate and Cox’s multivariate analyses were used to determine the prognostic significance. Results The median follow-up time was 100.4 months, and the median survival time was 20.3 months. The histopathological grade was an important independent prognostic factor in the univariate and multivariate analyses, and a higher grade was associated with poor overall survival and progression-free survival. After further stratification by the extent of resection and postoperative adjuvant treatment, the histopathological grade remained a significant prognostic factor. Conclusions In this study, histopathological grade affected survival in IDH-wild-type gliomas. This effect appears to be independent of the extent of resection and postoperative treatment. Thus, we suggest that clinical treatment of patients with IDH wild-type gliomas should continue to consider histopathological grade along with the molecular characteristics of the tumors.