SURG-03. COMBINATION LASER INTERSTITIAL THERMAL THERAPY PLUS SRS INCREASES TIME TO PROGRESSION FOR RECURRENT SRS-TREATED BRAIN METASTASES

Abstract

Abstract INTRODUCTION Laser interstitial thermal therapy (LITT) has evolved as an effective treatment for brain metastases (BM) failing stereotactic radiosurgery (SRS), and an alternative to open resection/repeat SRS. We sought to evaluate the efficacy of LITT+SRS in recurrent SRS-treated BM, and compare outcomes to LITT alone vs. repeat SRS. METHODS A multicenter, retrospective study was performed of patients with biopsy-proven BM recurrence after SRS. Patients were stratified by planned LITT+SRS vs. LITT alone vs. repeat SRS. Index lesion progression was determined by RANO criteria. RESULTS Forty-five patients fit inclusion, with a median follow-up of 7.3 months (range:1.1-30.5), age of 60 (range:37-86), KPS of 80 (range:60-100), and contrasted tumor volume (CTV) of 6.1cc (range:1.4-19.4). Histologies included NSCLC (44%), breast (24%), SCLC, melanoma, colon, and oroesophageal (< 10% each). Sixty-three percent of patients underwent LITT alone, 18% had repeat SRS, while 27% had LITT+SRS (post-LITT SRS). Median time to index lesion progression was greatest in the LITT+SRS group compared to LITT alone or repeat SRS (>23, 7.5, and 3.6 months, respectively [p=0.018]), as was overall survival (23.7, 5.9, and 7.0 months, respectively [p=0.023]). Age, sex, primary histology, CTV, and treatment strategy were univariate predictors of tumor progression; patients not treated with LITT+SRS were more likely to have index lesion progression (p=0.016). When controlling for histology and CTV in a multivariate model, patients not treated with LITT+SRS were significantly more likely to have progression (p=0.001). All LITT+SRS patients who experienced subsequent radiographic progression were diagnosed with recurrent tumor, while radiation necrosis incidence in the repeat SRS arm was 25%. CONCLUSION LITT+SRS appears superior to LITT alone or repeat SRS for treatment of biopsy-proven BM recurrence after SRS when controlling for other variables known to be predictive of progression. Prospective trials should be designed to validate the utility of combination LITT+SRS after SRS failure.