SURG-16. PREDICTORS OF LOCAL CONTROL FOLLOWING LASER INTERSTITIAL THERMAL THERAPY FOR GLIAL TUMORS

Abstract

Abstract INTRODUCTION Laser Interstitial thermal therapy (LITT) is a minimal-access procedure for intracranial tumors that are either refractory to standard treatment paradigms or difficult to access via conventional open surgery. OBJECTIVE To evaluate predictors of local disease control following LITT in patients with primary and secondary brain tumors. METHODS Single-center retrospective cohort study of all consecutive LITT ablations between 2014 and 2019. Demographic and procedural characteristics analyzed with respect to local disease control at 6 months. Chi-square tests for categorical variables, T-tests/Wilcoxon Rank-Sum tests for continuous variables for parametric and non-parametric data, respectively. Poisson regression models were used to approximate relative risk (RR) with 95% confidence intervals. RESULTS A total of 76 patients underwent LITT with a median follow up of 12.3 months; pathology at time of ablation was glioblastoma multiforme (GBM, 36%), WHO grade III primary CNS (24%), low grade CNS (20%), and metastatic lesions (19%) with respective local control rates of 26%, 20%, 29%, and 26%. Pathology of GBM (RR 0.46, 0.21-1.02, p=0.055) and a 5-year increase in age at the time of ablation (RR 0.91, 0.83-0.99, p=0.028) were associated with a lower likelihood of local control at 6 months. Preoperative Karnofsky performance status (KPS) of 100 (RR 2.04, 1.13-3.69, p=0.019) was associated with a higher likelihood of local control. Extent of ablation (EOA) demonstrated a direct relationship with local control; when EOA=100% local control was 59%, with this rate dropping down to 21% when EOA=90%. Tumor location, lesion volume, gender, BMI, ethnicity, or whether there existed multiple foci of disease at the time of ablation had no strong association with local control. CONCLUSION Our series demonstrates that preoperative performance status and age were strong predictors of local disease control following LITT. Incomplete ablation and histology of high-grade glioma portended a higher risk of local recurrence.