Quantitative Assessment of Tumor Contact with Neurogenic Zones and Its Effects on Survival: Insights beyond Traditional Predictors.

Simple Summary: The exact cellular origin of glioblastoma (GBM) remains uncertain, with prevalent theories suggesting emergence from transformed endogenous stem cells. These cells likely play pivotal roles in tumor initiation and progression. The impact of proximity of GBM to the brain's neurogenic zones on patient survival remains a lingering question. Our study investigated tumor infiltration into the subventricular zone (SVZ), the subgranular zone (SGZ) and the cortex alongside clinical variables, such as KPS score, multifocality and selected molecular markers. Utilizing a fully automated processing and segmentation pipeline, we objectively quantified these relationships in 177 IDH wild-type glioblastomas. Our findings support prior research indicating SVZ proximity as a predictor for poor survival, while SGZ proximity showed no significant impact. We also established new survival thresholds based on tumor mass fractions and minimal distances. Contrary to previous studies, we found no significant correlations between SVZ contact and multifocal growth pattern or MGMT promoter methylation. So far, the cellular origin of glioblastoma (GBM) needs to be determined, with prevalent theories suggesting emergence from transformed endogenous stem cells. Adult neurogenesis primarily occurs in two brain regions: the subventricular zone (SVZ) and the subgranular zone (SGZ) of the hippocampal dentate gyrus. Whether the proximity of GBM to these neurogenic niches affects patient outcome remains uncertain. Previous studies often rely on subjective assessments, limiting the reliability of those results. In this study, we assessed the impact of GBM's relationship with the cortex, SVZ and SGZ on clinical variables using fully automated segmentation methods. In 177 glioblastoma patients, we calculated optimal cutpoints of minimal distances to the SVZ and SGZ to distinguish poor from favorable survival. The impact of tumor contact with neurogenic zones on clinical parameters, such as overall survival, multifocality, MGMT promotor methylation, Ki-67 and KPS score was also examined by multivariable regression analysis, chi-square test and Mann–Whitney-U. The analysis confirmed shorter survival in tumors contacting the SVZ with an optimal cutpoint of 14 mm distance to the SVZ, separating poor from more favorable survival. In contrast, tumor contact with the SGZ did not negatively affect survival. We did not find significant correlations with multifocality or MGMT promotor methylation in tumors contacting the SVZ, as previous studies discussed. These findings suggest that the spatial relationship between GBM and neurogenic niches needs to be assessed differently. Objective measurements disprove prior assumptions, warranting further research on this topic. [ABSTRACT FROM AUTHOR]