I'd like to start off by thanking the AANS Scientific Committee for allowing me to present our work here today. My name is Matt Grabowski. I'm a PGY-6 neurosurgery resident at Cleveland Clinic, and the title of our presentation is Laser Interstitial Thermotherapy Followed by SRS Increases Time to Progression of Recurrent Brain Metastases Initially Treated with SRS. The authors had nothing to disclose. Improved survival among patients with brain metastases has been accompanied by a rise in tumor recurrence and SRS-treated lesions. About 10 to 15% of brain metastases recur after SRS, typically less than six months after treatment. Currently, there are limited treatment options. However, LIT has evolved as an effective treatment for both SRS failures and as an alternative to resection. While patients undergoing resection of recurrent brain metastases typically undergo repeat SRS, brain metastases differ as to whether patients post-LIT are treated with repeat SRS versus observation. At present, no study has examined the benefit of post-LIT SRS for recurrent brain metastases. The purpose of this study was to evaluate the comparative efficacy of the addition of adjuvant SRS to LIT in patients with biopsy-proven tumor recurrence after SRS. It was a multi-center, retrospective study of brain metastasis patients who underwent LIT plus or minus SRS for biopsy-proven tumor recurrence after SRS. Patients were stratified by planned adjuvant SRS versus no SRS. We collected imaging, demographic, and clinical variables, and radiographic tumor progression was determined by RANO criteria. Outcomes were compared by post-LIT SRS status. Here is a summary table describing our total patient cohort. Median follow-up was 7.3 months, and the median age of treatment was 60 years. Baseline KPS was a median of 80, with a variety of primary tumor pathologies, lung being the most common. 33% of patients underwent adjuvant SRS after LIT. 35% of patients experienced radiographic progression in the entire cohort, with a median time to progression of 14.75 months. On this slide, we have a Kaplan-Meier curve demonstrating the time to progression of our two treatment cohorts. In blue is the LIT alone group, while in red is the LIT plus SRS group. The LIT alone group had a median progression-free survival of about 7.5 months, whereas the LIT plus SRS group had a much longer median progression-free survival of greater than 21.3 months. This reached statistical significance. Next, we sought to identify univariate predictors of progression. Age, primary tumor histology, and treatment modality were identified as statistically significant univariate predictors. Patients not treated with SRS after LIT were 3.6 times more likely to have progression of their index lesion in a univariate model. When we utilized those variables for a multivariate model, when controlling for age and tumor histology, patients not treated with SRS after LIT were 10.7 times more likely to have progression of their index lesion. In conclusion, these data suggest that adjuvant SRS is warranted in LIT-treated brain metastasis lesions, failing initial SRS theory. Future directions for this project include incorporation of percent TDT coverage and tumor volumes into the analysis to control for these important variables, as well as work on designing a prospective trial to further validate the utility of adjuvant SRS after LIT in this patient group. Thank you.

Laser Interstitial Thermotherapy

Stereotactic Radiosurgery

brain metastases

tumor recurrence

adjuvant SRS