SURG-07. QUANTIFYING THE RISK OF SHORT TERM SEIZURES FOLLOWING LASER INTERSTITIAL THERMAL THERAPY

Abstract BACKGROUND Tumor-related epilepsy is a common sequela of both primary and metastatic brain tumors, as well as radiation necrosis (RN). Laser interstitial thermal therapy (LITT) is an effective option for lesional cytoreduction but induces transient peritumoral edema that typically resolves within 3 months of the procedure. Accordingly, we quantified the risk of seizure development early post-LITT in patients with tumors or RN of diverse histologies. METHODS Patients treated with LITT for brain tumors or radiation necrosis at a high-volume center from 2015 – 2021 with at least 3 months of clinical follow-up were evaluated for seizure risk and time to discontinuation of anti-epileptic drugs (AEDs) for at least 4 weeks, with censoring at death or last follow-up. RESULTS One-hundred and seventeen patients met inclusion criteria, and 22 (19%) experienced a post-LITT seizure within 3 months of surgery. Those with pre-LITT seizures (P = 0.03), prior whole-brain radiation (WBRT) (P = 0.0099), or lower pre-operative KPS (P = 0.04) were more likely to have a post-LITT seizure. Frontal lobe tumors appeared to be more frequently associated with seizures (68% vs 45%, P = 0.06). Prior WBRT, odds ratio (OR) 4.27 (95% CI 1.01 – 18.55), P = 0.047 and pre-LITT seizure, OR 5.39 (95% CI 1.87 – 16.31), P = 0.002 remained predictive on multivariate analyses. Successful AED weaning occurred at a median of 1.68 months (no seizure within 3-months group) versus undefined for patients experiencing seizures (P = 0.015). Post-LITT seizures within 3 months were associated with worsened post-LITT overall survival, 5.95 vs 17.2 months, P < 0.0001. DISCUSSION Prior seizure history or previous WBRT pose a risk of breakthrough seizures following laser ablation. Neurosurgeons should consider extended AED treatment or referral for management of tumor-related epilepsy in patients with these neurologic risk factors.