# Prognostic Factors of IDH Wild-Type Glioblastoma After Extensive Surgery: A Multimodal Atlas of Tumor Locations, Recurrences and Management

## TL;DR

This study explores how tumor location and recurrence patterns affect survival in glioblastoma patients after extensive surgery.

## Contribution

The study introduces a multimodal atlas to analyze tumor recurrence locations and their impact on survival in IDH wild-type glioblastoma patients.

## Key findings

- Initial tumor location in the corpus callosum is linked to lower overall survival.
- Multifocal recurrences are associated with specific tumor locations like the corpus callosum and frontal left regions.
- Complete resection near the subventricular zone may reduce its influence on survival.

## Abstract

Glioblastoma is one of the most aggressive tumors of the brain despite complete resection of the contrast enhancement. The aim of our retrospective study was to identify the pattern of recurrence after complete resection. We showed that in such a homogeneous group of patients, overall survival might be low according to initial (corpus callosum) and recurrence location (left atrium). Multifocal recurrences seemed to be correlated with tumor location (corpus callosum, frontal left, and temporal bilateral) whereas relationship between the subventricular zone and overall survival seemed to be more complex and might depend on the extent of resection and tumor location. We also showed that even in complete resection, 92% of recurrence occurred in the vicinity of the postoperative cavity. These findings also suggest identifying new strategies to improve the local control of the disease even after large surgery.

Introduction: Glioblastomas have poor prognosis despite aggressive treatment. Patterns of recurrence and overall survival (OS) can be very different. The population with complete resection having a so-called good prognosis can nevertheless present poor OS. Our purpose was to assess the OS and patterns of recurrence thanks to multimodal statistical maps in glioblastoma with large extent of resection (residue < 10 mL). Methods: adult patients presenting IDH wild-type glioblastoma between 2013 and 2019 were selected. Clinical data and MRI characteristics were collected. Preoperative, postoperative, and recurrence volumes were segmented and normalized in the MNI space to compute statistical maps. Log-rank test and Cox model were used to assess OS and prognosis factors. Results: 60 patients were included. Mean residual volume was 0.89 ± 2 mL. Median OS was 22.3 months (95% CI: (20–35)). Initial location in the corpus callosum was associated with low OS (317 vs. 783 days, HR = 0.46, p = 0.003). At recurrence, KPS > 90 and tumor volume < 10 mL were associated with higher OS (p =0.006 and p = 0.05). Tumor contact with the SVZ as well as multifocal recurrence did not show any impact on the OS. Conclusions: High OS can be obtained thanks to surgery with residual volume < 10 mL. Invasion of the corpus callosum at diagnosis is associated with a poor prognosis despite a large extent of resection. Results suggest that large resection near the SVZ might decrease its putative influence on OS.