SURG-11. THE ROLE OF MAGNETIC RESONANCE-GUIDED LASER ABLATION FOR INTRACRANIAL METASTATIC TUMORS

INTRODUCTION: Laser interstitial thermal therapy (LITT) is a novel, minimally-invasive adjuvant therapy that is well-suited for intracranial tumors in deep or critical areas, recurrences failing standard therapy, and poor open-surgical candidates. To better characterize safety and clinical outcomes, we present the largest single-institutional experience with LITT for recurrent brain metastases. METHODS: All patients undergoing LITT for single recurrent brain metastases from 2013–2018 at the University of Miami were included in this study. Primary outcomes included extent of ablation (EOA), time-to-recurrence (TTR), and overall survival (OS). Secondary endpoints include neurologic status and complication rate. Kaplan-Meier survival analysis was performed to quantify TTR and OS, compare outcomes by primary tumor of origin, and identify potential predictors of TTR and OS. RESULTS: Thirty-six patients underwent 44 LITT procedures; all had undergone prior treatment with stereotactic radiosurgery (SRS). Mean age was 56.8 years and 83.3% were female. Average pretreatment tumor volume was 6.6cm3. Patients were treated with a mean ablation dose of 12.4W (9.8-14W), achieving a median EOA of 100% (range 55–100%). At median follow-up of 11.6 months (IQR 4.6–19.1 months), 34 of 44 (87.3%) cases had tumor control on radiographic imaging and 22 of 36 (61.1%) of patients remain alive. Median TTR was 55.9 months; median OS was 25.5 months. Neither TTR nor OR differed significantly by primary tumor of origin (P >.05). EOA >88% predicted longer TTR (P=.01) Neurologic status was stable or improved in all surviving patients. No major complications occurred (0% rate). CONCLUSIONS: Our institutional experience demonstrates LITT is safe for intracranial metastases resistant to SRS and offers several advantages over open surgical treatment. TTR and OS were not associated with primary tumor of origin. A threshold EOA >88% predicted longer TTR. Randomized studies are needed to evaluate the role of LITT as a treatment adjunct.