Potential and Pitfalls of Postoperative Volumetric Assessment of Extent of Resection in High-Grade Glioma in Resource-Constrained Settings.

Background: While literature suggests the need for routine postoperative volumetric estimation of the EOR and residual tumour volume (RTV) in all cases of gliomas, the utility and feasibility of this protocol in resource-constrained centers remain underinvestigated.

Objectives: Our objective was to study the feasibility of volumetric EOR in routine neurosurgical practice and determine correlation with surgeons' intraoperative estimation of EOR. The secondary objective was to determine the survival impact of EOR and RTV on survival.

Methods and materials: A prospective study of pathologically proven high-grade gliomas (WHO grades 3 and 4) in adults was conducted at a tertiary care center. Pre- and postoperative magnetic resonance imaging (MRI) was obtained for volumetric analysis using OsiriX software and manual segmentation. Overall survival and predictors were studied using Kaplan-Meier and Cox regression analysis.

Results: Postoperative volumetry was feasible in 31% patients (n = 25) of study eligible patients (n = 84). The median EOR, CE-PTV, and CE-RTV were 79.1%, 69.8 cm3, and 8.7 cm3, respectively. There was a poor correlation of surgeons' intraoperative impression and volumetric data (P = 0.359). Interestingly, the EOR was not significantly associated with the survival time (P = 0.920), while tumor grade, molecular profile, Ki 67 score, and postoperative functional status showed statistically significant impact.

Conclusion: Logistic difficulties impede routine implementation of this protocol in developing countries. MRI volumetry is clearly more accurate than surgeons' intraoperative estimation of EOR. Notwithstanding the role of EOR in survival, our study reveals a perhaps bigger impact of tumor biology and postoperative functional status in this equation.