Prognostic Factors and Oncofunctional Outcomes of WHO 2021-Classified Insular Gliomas Undergoing Awake Brain Mapping

This study aimed to evaluate prognostic factors and oncofunctional outcomes, including neurological and neurocognitive preservation, in patients with World Health Organization 2021-classified insular lower-grade gliomas and glioblastoma who underwent awake brain mapping.

We retrospectively analyzed 36 consecutive patients with insular glioma, including LrGGs and GBM, who underwent awake surgery between December 2012 and January 2021.

The group of patients with IDH-mutant LrGG included 23 cases, while those with IDH-wildtype GBM with histological features of LrGG and GBM included 5 and 8 patients, respectively. The postoperative mean Wechsler Memory Scale-Revised scores for General Memory (Z=-0.56, P=0.04) and Delayed Recall (Z=-0.73, P=0.04) significantly improved compared with their preoperative values after awake surgery. The median overall survival (OS) of patients with IDH-mutant LrGGs was significantly longer (not reached) than that of patients with IDH-wildtype GBM with histological LrGG (15 months, P<0.001) and IDH-wildtype GBM with histological GBM (12 months, P<0.001). The multivariate models showed that OS rates were significantly related to pathology [histological GBM versus histological LrGG, hazard ratio (HR)=6.41, P=0.04], IDH1 or IDH2 status (mutation vs. wildtype, HR=0.04, P=0.01), and final EOR (≥90% vs. <90%, HR=0.12, P=0.04).

Histological GBM, IDH mutation status, and EOR ≥90% were significant predictors of OS in patients with insular gliomas. Moreover, awake functional mapping for insular gliomas is a useful surgical approach, as it minimizes neurological deficits and allows preservation of neurocognitive functions.