865 Survival Benefit of Stereotactic Laser Ablation (SLA) in Newly Diagnosed Glioblastoma Patients: A Matched Cohort Analysis

Abstract

INTRODUCTION: Post-hoc analysis of a previously published matched cohort study suggests improved survival for glioblastoma patients who underwent stereotactic laser ablation (SLA) relative those who underwent a biopsy, particularly for tumors where contrast enhancing (CE) regions were completely covered by thermal ablation. METHODS: Thirteen patients with newly diagnosed isocitrate dehydrogenase (IDH) wild type glioblastomas (without H3K27 mutation) who underwent SLA with ablation coverage of >90% of the contrast enhancing region were identified. Control cohort was generated by screening patients who underwent stereotactic biopsy for a newly diagnosed tumor matched for: age (+/- 10 years), location, tumor volume (+/- 30% of CE volume), and methyl-guanine methyl-transferase (MGMT promoter methylation status). Post-operative course, complications, 30-day readmission, and overall survival data were collected. RESULTS: The mean KPS for the SLA and biopsy cohorts were comparable (SLA: 90+14; biopsy: 87+16). One patient (8%) in the SLA cohort experienced new-onset diplopia, and one biopsy-only patient (8%) suffered hemi-sensory alteration. There were no 30-day readmissions for either cohort. With a median follow-up of 283 days, the median survival (mOS) for 375 days (∼13 mo) for the SLA treated patient cohort and 264 days (∼ 9 mo) for the biopsy cohort (p = 0.026). To exclude the possibility that this survival difference was due to selection of prognostically favorable patients for SLA, the survival benefit was confirmed by comparison to a second matched biopsy-only glioblastoma cohort from another institution without capacity for SLA. When stratified by MGMT promoter methylation, SLA survival benefit was significant in only patients with methylated tumors (SLA mOS: 620 days (21 mo); biopsy mOS: 171 days (5.7 mo), p = 0.007) CONCLUSIONS: For MGMT promoter methylated glioblastomas, SLA treatment was associated with improved survival relative to biopsy-treated patients. Validation of this finding in a prospective study is warranted.