Impact of intraoperative-brain-mapping subtypes on progression-free survival in patients with tumor-related-epilepsy glioblastoma involving function-related areas: Experience from a single Mexican-center

Objective The present study evaluates the correlation between Intraoperative-Brain-Mapping (IBM)-subtypes and their effect-on-survival in a Tumor-related-epilepsy (TRE) glioblastoma (GB) patients cohort. Methods We conducted a retrospective, single-center chart review of consecutive adult patients with TRE-GB treated between 2015 and 2022. Patients were categorized according to the IBM subtype performed during surgery (motor BM vs non-motor IBM). Associations between IBM subtype and clinical variables were examined using bivariate analyses (chi-square test). Progression-free-survival (PFS) and overall survival (OS) were estimated with Kaplan-Meier methods, and Cox proportional hazards model were used to identify independent predictors of survival. A p value < 0.05 was considered statistically significant. Results Forty-eight TRE-glioblastoma patients were included. Mean age was 65.96 SD ± 13.61, and 60.4% were male. All cases underwent IBM (41.7% involving motor, 37.5% language, and 20.8% visual function mapping). 73% were treated with an awake-craniotomy (AC). GTR was obtained in all cases treated with motor-IBM, compared to 54% of non-motor-IBM cases (p < 0.001). Median OS was 13.42 months, and median PFS was 10 months. Motor-IBM was significantly related to a longer PFS (14vs. 6 months, p < 0.001) and OS (15vs.14 months, p < 0.001) compared to non-motor IBM cases. AC cases with non-motor IBM presented worse PFS (6 vs.14 months,p < 0.001) and OS (10 vs.16 months,p = 0.013). During follow-up, 27% of cases presented Engel-IA. Adequate seizure-control (Engel-IA) and a better quality-of-life (QOLIE-10-P<2.8) were significantly associated with longer survival (p < 0.05). Cox analysis demonstrated that preoperative KPS (HR = 0.974, 95% CI 0.950-0.999, p = 0.044), seizure type (non-FBTCS, HR = 0.452, 95% CI 0.219-0.937,p = 0.033) and motor-IBM (HR = 0.380, 95% CI0.156-0.927, p = 0.033) are independent favorable factors for progression-free-survival. Conclusions Patients treated with motor-IBM in TRE-glioblastoma involving the motor cortex and/or corticospinal tract presented a longer PFS and OS. Non-motor IBM cases (visual or language) showed a less favorable outcome because a limited EOR was required to preserve function. Although an AC-IBM methodology was indicated, TRE-GB cases with non-motor IBM presented poorer survival rates. An adequate postoperative seizure-control (Engel-IA) with a positive quality-of-life impact (QOLIE-10-P<2.8) was also associated with longer survival in our series.