Combining Laser Interstitial Thermal Therapy With SRS Improves Time to Progression for Recurrent SRS-Treated Brain Metastases

Abstract

Improved survival for patients with brain metastases (BM) has been accompanied by a rise in tumor recurrence after stereotactic radiosurgery (SRS). Laser interstitial thermal therapy (LITT) has evolved as an effective treatment for SRS failures and an alternative to open resection or repeat SRS. We aimed to evaluate the efficacy of LITT followed by SRS (LITT+SRS) in recurrent SRS-treated BM, and to compare outcomes to LITT alone vs. repeat SRS alone.A multicenter, retrospective study was performed of patients who underwent treatment for biopsy-proven BM recurrence after SRS. Patients were stratified by planned LITT+SRS vs. LITT alone vs. repeat SRS alone. Index lesion progression was determined by RANO criteria.Forty-five patients met inclusion criteria, 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 pre-procedure contrasted tumor volume (preCTV) of 6.1cc (range:1.4-19.4). Primary diagnoses included NSCLC (44%), breast cancer (24%), SCLC, melanoma, colon cancer, and oroesophageal cancer (< 10% each). 27% of patients underwent LITT+SRS, 56% LITT alone, and 18% SRS alone. Median time to index lesion progression (> 23, 7.5, and 3.6 months, respectively [P = 0.018]) and overall survival (23.7, 5.9, and 7.0 months, respectively [P = 0.023]) were significantly improved with LITT+SRS compared to LITT or repeat SRS alone. On univariate analysis, age, sex, primary histology, preCTV, and treatment strategy predicted tumor progression. Blue thermal dose threshold (TDT) line ablation coverage predicted progression with LITT alone, but not with LITT+SRS. In a univariate model, patients not treated with LITT+SRS were more likely to have index lesion progression (P = 0.016). When controlling for tumor histology and preCTV in a multivariate analysis, patients not treated with LITT+SRS remained significantly more likely to have index lesion progression (P = 0.001). All patients undergoing LITT+SRS who experienced subsequent radiographic progression were diagnosed with recurrent tumor, whereas patients treated with SRS alone had a 25% incidence of radiation necrosis.These data suggest that LITT+SRS is superior to LITT or repeat SRS alone for treatment of biopsy-proven BM recurrence after SRS failure, even after controlling for variables known to predict progression. Prospective trials are warranted to validate the efficacy of using combination LITT+SRS for treatment of recurrent BM previously treated with SRS.E.J. Vaios: None. M. Grabowski: None. E. Srinivasan: None. D. Huie: None. E. Sankey: None. B. Otvos: None. M. Olufawo: None. A. Scott: None. A.H. Kim: None. E.C. Leuthardt: None. G.H. Barnett: Consultant; Monteris Medical, Inc. A.M. Mohammadi: None. Z. Reitman: None. S.R. Floyd: Instructor in a company-sponsored training course designed for new users of the CyberKnife system; Accuray Incorporated. J.P. Kirkpatrick: None. P. Fecci: None.