The impact of the subventricular zone invasion types and MGMT methylation status on tumor recurrence and prognosis in glioblastoma

Abstract

Purpose: The prognosis of isocitrate dehydrogenase (IDH) wild-type glioblastoma (GBM) with the subventricular zone (SVZ) invasion is extremely unfavorable but the underlying mechanism remains unclear. We aimed to conduct a retrospective study to mainly investigate the prognostic value of SVZ invasion and MGMT status, and developed a novel clinical prediction model based on our findings. Methods: 139 patients with IDH wild-type GBM were retrospectively studied. They were categorized into four types, taking into consideration of the spatial positional relationship between tumor, SVZ and the cerebral cortex (Ctx) on the preoperative T1-weighted contrast-enhanced images (T1WI + C). Survival analysis was conducted to identify significant variables, which were then included in a clinical model to predict patient survival outcomes. Results: Among the included patients, 41 (29.5 %) were type I, 23 (16.5 %) were type II, 59 (42.4 %) were type III, and 16 (11.5 %) were type IV. In Cox regression analysis, partial surgical resection, SVZ invasion, MGMT unmethylation, short adjuvant chemotherapy cycles, and distant recurrence were identified as independent risk factors of prognosis. A clinical prediction model based on these factors was developed to accurately predicted the survival outcome at 6, 12, and 18 months. Conclusion: Both SVZ invasion and MGMT unmethylation negatively influenced the prognosis of patients with IDH wild-type GBM. The clinical model developed in this study accurately predicts the survival outcome, providing a basis and reference for clinical practice.

Keywords

• Glioblastoma
• Subventricular zone
• MGMT
• Imaging classification
• clinical prediction model