P01.17.A Role of preoperative assessment in predicting tumor induced plasticity in patients with diffuse gliomas

Abstract

Abstract Background When diffuse gliomas (DG) affect the brain′s potential to reorganize functional networks, patients can exhibit seizures and/or language/cognitive impairment. The tumor-brain interaction and the individual connectomic organization cannot be predicted preoperatively. We aimed to, first, investigate the relationship between preoperative assessment and intraoperative findings of eloquent tumors in 36 DG operated with awake surgery. Second, we also studied possible mechanisms of tumor-induced brain reorganisation in these patients. Material and Methods FLAIR-MRI sequences were used for tumor volume segmentation and the Brain-Grid system (BG). This standardized radiological tool was used as an overlay for infiltration analysis. Neuropsychological (NPS) and/or language preoperative assessments were performed in all patients before the direct cortical/subcortical brain mapping. The distance between eloquent spots and tumor margins was registered and measured on the neuronavigation system. Tumours containing eloquent points within hyperintense area on FLAIR sequences (cortical or subcortical) were considered eloquent. Eloquent points within 5-10 mm from the FLAIR signal margin were considered peritumoral, while beyond 10 mm from the FLAIR signal were considered outside the tumour area. Pre and postoperative images (3 months after the operation) were merged to detect eventual residual tumour. Clinical, radiological, and topographical variables and intraoperative findings were used for correlation and logistic regression analyses. Results 84.6% of our patients displayed neuropsychological symptoms at the preoperative assessment. Eloquent tumors were detected in 75% of the cases. Impaired NPS functions were correlated with more invasive tumors, crucial location (A4C2S2/A3C2S2-voxels, left opercular-insular/sub-insular region) and higher risk of eloquent tumors. Epilepsy was correlated with larger tumor volumes and infiltrated A4C2S2 /A3C2S2 voxels. Language impairment was correlated with infiltrated A3C2S2 voxel. Group comparison between younger and older patients (cut-off at 38 years old based on ROC curves) showed a significative difference in the number of intratumoral cortical eloquent spots (p < .05) and the number of peritumoral cortical eloquent spots (p < .001). Conclusion Preoperative NPS impairment was linked with high risk of eloquent tumors. Epilepsy and language impairment were linked with specific tumor locations while peritumoral cortical eloquent spots reflected an early compensative mechanism with age as possible influencing factor. A systematic integration of extensive cognitive assessment and advanced neuroimaging can improve our comprehension of the connectomic brain organization at the individual scale and lead to a better oncological/functional balance.