SURG-02. INTRAOPERATIVE RADIOTHERAPY FOR BRAIN METASTASES: EVALUATION OF ELECTROCORTICOGRAPHY AND PERI-OPERATIVE SEIZURE RISK

Abstract

Abstract BACKGROUND Intraoperative radiotherapy (IORT) has emerged as a viable tool for consolidation of surgery and radiation for brain metastases into a single episode of care, but its relative novelty compared to SRS or fractionated radiotherapy warrants evaluation of its safety. While post-operative seizure risk is typically minimal with the use of anti-epileptic drugs during the peri-operative phase, the risk of intra-operative epileptiform discharge remains unknown. METHODS Five consecutive cases of surgically resected brain metastases treated with IORT underwent electrocorticography via direct cortical electrode recordings adjacent to the resection cavity with paddle electrodes used for mapping of phase reversal. Continuous recordings were made before, during, and after radiation delivery and analyzed for evidence of radiation-associated changes. RESULTS No evidence of significant electrophysiological change was noted in any of the cases, nor was there any clinical evidence of seizure in the immediate peri-operative period. These data represent the first direct cortical recordings in human subjects during the delivery of radiation. CONCLUSIONS In this small cohort of IORT treated resected brain metastases, the delivery of intra-operative radiation does not appear to impact cortical activity or precipitate post-operative seizures. Further studies are needed to determine the long-term incidence of treatment associated changes if they exist.