Histopathological grading affects survival in patients with IDH-mutant grade II and grade III diffuse gliomas. (September 2020)

• Record Type: Journal Article
• Authors: Franceschi, Enrico; Tosoni, Alicia; Bartolini, Stefania; Minichillo, Santino; Mura, Antonella; Asioli, Sofia; Bartolini, Daniela; Gardiman, Marina; Gessi, Marco; Ghimenton, Claudio; Giangaspero, Felice; Lanza, Giovanni; Marucci, Gianluca; Novello, Mariangela; Silini, Enrico M.; Zunarelli, Elena; Paccapelo, Alexandro; Brandes, Alba A.
• Is Part Of: European journal of cancer. Volume 137(2020)
• Page Start: 10
• Page End: 17
• Publication Date: 2020-09
• Subjects: Gliomas -- Grade II -- Grade III -- IDH mutation -- 1p19q codeletion -- Survival; Cancer -- Periodicals; Neoplasms -- Periodicals; Cancer -- Périodiques; Cancer; Tumors; Electronic journals; Periodicals; Electronic journals; 616.994
• DOI: 10.1016/j.ejca.2020.06.018
• Languages: English
• ISSNs: 0959-8049

Abstract

Abstract: Background: Diffuse grade II and grade III gliomas are actually classified in accordance with the presence of isocitrate dehydrogenase mutation ( IDH -mut) and the deletion of both 1p and 19q chromosome arms (1p/19q codel). The role of tumour grading as independent prognostic factor in these group of tumours remains matter of debate. The aim of this study was to determine if grade is an independent prognostic factor and not somehow associated to IDH mutation and 1p/19q status of the tumour. Methods: We analysed 399 consecutive patients with newly diagnosed, histologically proven World Health Organisation (WHO) 2016 grade II or grade III IDH -mut gliomas, assessed by polymerase chain reaction, immunohistochemistry or next-generation sequencing (NGS). Results: The analysis included 399 patients with grade II (n = 250, 62.7%) or grade III (n = 149, 37.3%) diffuse gliomas. Median follow-up time was 105.3 months. Median survival was 148.1 months. In multivariate analysis, grade II (hazard ratio [HR] = 0.342, 95% confidence interval [CI]: 0.221–0.531; P < 0.001) and 1p/19q codeletion (HR = 0.440, 95% CI: 0.290–0.668; P < 0.001) were independently associated with a lower risk for death. The difference in survival remained significant (p = 0.006 in astrocytomas, p = 0.014 in oligodendrogliomas) when adjusted for histological subtype. Residual disease after surgery (or biopsy) negatively affected survival (HR: 2.151, 95% CI: 1.375–3.367, P = 0.001). Post-surgical treatment with radiotherapy + adjuvant chemotherapy improved survival compared with follow-up and other treatments (HR: 0.316, 95% CI: 0.156–0.641, P = 0.001). Conclusions: In our study, histopathological grade still affects survival in IDH -mutant WHO grade II and III diffuse gliomas. This effect appears to be independent from molecular features, extension of surgical resection and post-surgical treatments. Therefore, physicians should continue to take into account tumour grade, along their molecular characteristics, for a better clinical and therapeutic management of the patients. Highlights: Grade II/III gliomas are classified in accordance with IDH mutation and 1p/19q deletion. The role of grading as an independent prognostic factor remains matter of debate. In our study, histological grade affects survival in IDH -mut grade II and III gliomas. The impact of grade on survival is independent from clinical and molecular factors.