10318-ST-9 Surgical Management of Adult Thalamic Gliomas: Reappraisal of Indications Based on the Risk of Postoperative Morbidity

Abstract Objective Adult thalamic gliomas are malignant tumors located in deep brain structures, where predicting functional outcomes and determining surgical indications remains difficult. This study aimed to reassess surgical indications by analyzing postoperative clinical courses and related factors. Methods We retrospectively reviewed 20 adult patients (12 men, 8 women; median age, 45. 5 years) who underwent resection of thalamic gliomas at our institution between 2011 and 2019. Parameters evaluated included extent of resection, progression-free survival (PFS), overall survival (OS), tumor location, intraoperative motor evoked potential (MEP) changes, severity of postoperative hemiparesis, and changes in Karnofsky Performance Status (KPS). Results All tumors were IDH-wildtype: 9 diffuse midline gliomas (DMG), 10 glioblastomas (GBM), and 1 not otherwise specified. Mean extent of resection was 94. 9%. Median OS and PFS were 22.5 and 17 months, respectively. DMG and GBM showed OS/PFS of 21.2/15.2 and 13.4/7. 1 months. Hemiparesis occurred regardless of MEP changes, and severity correlated with deep sensory deficits (P = 0.007). Postoperative KPS declined in 7 cases (41. 2%), was unchanged in 7 (41.2%), and improved in 3 (17.6%). Age, tumor size, preoperative KPS, and MEP deterioration were not significant predictors of hemiparesis. However, medially located tumors showed a tendency toward better recovery than lateral or anterior types. Conclusion Aggressive resection may extend survival in adult thalamic gliomas. However, hemiparesis can develop even without intraoperative MEP changes, especially with coexisting sensory deficits. These findings underscore the need to weigh postoperative functional outcomes when considering surgery.