503 Functional Outcomes Following Laser Ablation Versus Resection of Motor Cortex Metastases

INTRODUCTION: Laser interstitial thermal therapy (LITT) is used to treat radiographically progressive brain metastases following stereotactic radiosurgery (SRS), while resection has been reserved for large, symptomatic lesions in the upfront setting. Resection-associated morbidity in eloquently-located metastases may hinder definitive management. METHODS: Patients receiving resection or LITT for brain metastases associated with the primary motor cortex (PMC) from 2015-2023 were retrospectively reviewed. Clinicodemographic and survival data were collected, with patient Karnofsky Performance Status (KPS) or modified Rankin Scale (mRS) scores assessed out to 1-year by independent raters. RESULTS: Forty-one patients underwent resection and 30 underwent LITT to a PMC-associated lesion during the study period. Median age was 67 (range 38 – 80) years for resections versus 65 (44 – 80) for LITT; median pre-operative KPS (70 vs 80, P = 0.1) or mRS (2 vs 2, P = 0.66) did not differ between groups. Resected lesions were of larger median diameter than LITT treated lesions, 2.8 vs 1.9, P = 0.0001. Length of stay was longer for resections versus LITT, median 2 vs 1 day, P =0.0002, and the ICU was more frequently used (75.6% versus 20.0%, P < 0.0001). At 1 month from surgery, 66.7% of resection patients and 51.7% of LITT patients had stable or improved symptoms from pre-op, P = 0.21. This gap closed at 3 months, where 65.7% and 62.9% of patients in either cohort demonstrated symptom stability or improvement. Further, there was no significant decrement in KPS or mRS score out to a year for both LITT and resection. Overall survival was 11.5 vs 7.5 months for resections versus LITT, respectively, P = 0.99. CONCLUSIONS: LITT in the motor cortex may result in short-term motor deficits which ultimately recover in the long-term. Patients should be counseled accordingly.