SURG-38. SAFETY AND EFFICACY OF COMBINATORIAL IMMUNE CHECKPOINT BLOCKADE AND LASER INTERSTITIAL THERMAL THERAPY

Abstract

Abstract INTRODUCTION Treatment of intracranial lesions with laser interstitial thermal therapy (LITT) allows for simultaneous cytoreduction and the potential to generate an anti-tumor immune response. The safety and efficacy of combination immune checkpoint blockade (ICB) and LITT has not been determined. METHODS All patients who received LITT for neuro-oncologic indications at a single NCI-designated cancer center from 2015 – 2022 were included. Simultaneous ICB was defined as receipt of therapy within 6 weeks of LITT. Demographic, clinical, and survival data were collected. Immune-related and intracranial adverse events (iRAEs and IAEs) were graded according to Common Terminology Criteria. RESULTS Twenty-four patients received simultaneous LITT and ICB. Median age was 62 (range 40 - 78) and 12 (48%) were female. Median KPS was 80 (50 – 100). Use of ICB increased during the study period (r = 0.69). The most common pathology was non-small cell lung cancer (15 patients, 62.5%), followed by melanoma in 3 (12.5%) and 2 (8.3%) patients each with renal cell carcinoma or high-grade glioma. Twenty-three (96%) patients received single agent ICB, with pembrolizumab most common (12, 50%), followed by nivolumab (6, 25%). The median interval between LITT and ICB was 2.56 (0.85 – 4.98) weeks. The most common iRAE was hypothyroidism in 4 (16.6%) patients, with grade 3 pneumonitis in one patient. The most common IAE was seizures in 4 (16.6%) patients. Local progression was seen in 4 patients (16.6%), with a post-LITT overall survival of 20.6 (1.0 – 36.1) months for the cohort. CONCLUSIONS Combination LITT and ICB appears safe and effective, with iRAEs commensurate with trials of checkpoint inhibition. High-grade intracranial toxicity was rare. Prospective studies of combinatorial LITT + ICB are needed to establish biomarkers and optimal timing.