RADT-12. PRE- AND POST-OPERATIVE RADIATION TREATMENT PLANNING FOR PATIENTS RECEIVING STEREOTACTIC RADIOSURGERY FOR BRAIN METASTASES: A VOLUMETRIC ANALYSIS

Abstract BACKGROUND Pre-operative stereotactic radiosurgery (SRS) has emerged as a recent treatment option to treat large or symptomatic brain metastases. Compared post-operative SRS, pre-operative may reduce rates of radiation necrosis (RN) and meningeal disease through treating smaller volume by preventing tumor seeding. We hypothesize that volumes will be than volumes, which in turn lead decreased morbidity. METHODS A retrospective analysis was conducted patients who had surgical resection SRS fractionated (FSRT) for posterior fossa metastasis were eligible inclusion. Both MRIs required allow accurate target delineation. added each patient, the clinical (CTV) used included. cavity compared using Wilcoxon signed rank test. RESULTS 28 received FSRT from 1/1/2016-12/31/2020 included this analysis. The mean 14.9 ccs, CTV 21.0 ccs (p < 0.01). 75% initial size planning. For with at least 4 follow up (n = 8), progressively 18.9 8.1, 7.1, 6.9, 6.2 ccs. CONCLUSIONS In study evaluating lower most patients. Previous studies including PROPS-BM have shown how risk RN because are used. metastases requires prospective validation.