SURG-03. Indications of awake surgery for elderly patients with gliomas

BACKGROUND Awake surgery aims to maximize tumor resection while preserving critical brain functions, supporting better postoperative quality of life. While the Japanese guidelines recommend awake surgery for patients aged 15–65 years, many individuals over 65 remain active in daily and social life. This study assessed the feasibility and indications for awake surgery in elderly patients with gliomas. METHODS We retrospectively analyzed 40 glioma patients aged ≥ 65 years (mean age 71.2) who were scheduled to undergo awake surgery. Tumor grades included WHO grade 2 (n=6), grade 3 (n=9), and grade 4 (n=25). Twenty-eight patients were undergoing their first surgery, while 12 had prior surgeries. Patients were categorized into “complete” and “incomplete” groups based on whether intraoperative awake monitoring was successfully completed. To identify factors influencing awake surgery success, we performed multiple logistic regression and receiver operating characteristic (ROC) curve analysis using variables such as age, sex, WHO grade, tumor laterality and location, tumor volume, preoperative Karnofsky Performance Status (KPS), surgical history, and cognitive test scores. The Chi-square test was used to compare KPS scores between groups. RESULTS Awake surgery was completed in 65% of patients. Primary reasons for failure included insufficient awareness (36%), difficulty understanding tasks (29%), and severe symptoms (14%). Preoperative KPS (p=0.032) and surgical history (p=0.0050) were significant predictors. ROC analysis identified optimal thresholds as KPS ≥ 90 and first surgery (AUC = 0.87, sensitivity = 0.82, specificity = 0.86). Patients with both factors were significantly more likely to complete awake monitoring (p=0.00026). At three months, 89% of the complete group maintained KPS ≥ 80, compared to 36% in the incomplete group (p=0.00039). CONCLUSIONS Awake surgery in elderly patients is feasible and can lead to favorable functional outcomes when patients have a KPS ≥ 90 and are undergoing their first surgery.