Beschreibung:
<jats:title>Abstract</jats:title>
<jats:p>Detection of IDH mutations in patients with diffuse malignant astrocytomas resulted in substantial modifications in the WHO classification. An important observation was that patients with anaplastic astrocytomas (AA) IDH-wt had a clinical course similar to that glioblastoma (GBM) patients. The observations of the GGN and NOA-04, were based on mixed cohorts. While most GBM patients received combined radiochemotherapy, patients with AA usually only had radiotherapy or chemotherapy. This shortcoming raises the question whether AA IDH-wt patients did not behave prognostically better than GBM patients when receiving combined radiochemotherapy. Thus, the question remains whether the established histopathological grading criteria for malignant astrocytomas in the absence of IDH mutations are important if vascular proliferation or necrosis are undetectable. All patients investigated here with diagnosis of a malignant astrocytoma received combined standard radiochemotherapy independently of the histopathological diagnosis. Thus, the analysis allows to clarify whether patients with AA of IDH-wt have a prognosis similar to that of GBM patients under equivalent therapeutic conditions. We determined the IDH1/2 status by sequencing, the MGMT status by pyrosequencing. Patients with the histopathological diagnosis of an AA IDH-wt showed a comparable and therefore no better prognosis (median overall survival (mOS) 16 months) than patients with a glioblastoma (mOS 13 months). Instead, patients with an AA IDH-mut receiving same therapy had a mOS of 54 months. Thus, it can be concluded that in absence of IDH mutations, the established histopathological grading criteria ‘necrosis’ and ‘vascular proliferation’ lose their prognostic significance. If, on the other hand, patients with malignant astrocytomas and IDH mutations are examined, there is a difference between patients showing necrosis and/or vascular proliferation and those whose tumors do not. Accordingly, for patients with malignant astrocytomas with IDH mutations it can be concluded that differentiation between AA IDH-mut and GBM IDH-mut remains beneficial from a prognostic perspective.</jats:p>