MET-01 INDICATION AND OUTCOME OF SALVAGE SURGERY FOR LOCAL PROGRESSION OF BRAIN METASTASIS PREVIOUSLY TREATED WITH STEREOTACTIC IRRADIATION

PURPOSE: To determine treatment outcome following salvage surgery (SS) for local progression of brain metastasis treated by stereotactic irradiation (STI). METHODS: The clinical records of patients who underwent SS of local progression of brain metastases after STI at our institute between October 2002 and July 2019 were retrospectively reviewed. Kaplan-Meier curves were used for the assessment of overall survival (OS). The decision to perform SS was based on findings of magnetic resonance imaging and/or clinical evidence of local progression of the brain metastases and status of systemic disease. Prognostic factors for survival were analyzed; age, sex, primary cancer, RPA classification at surgery, extent of resection, radiotherapy after salvage surgery, and pre-surgical neutrophil-to-lymphocyte ratio (NLR). RESULTS: Fifty-four SS of 48 patients were performed. The median age of the patients was 63 years (range 36–79). The median interval from STI to SS was 12 months. The median overall survival was 20.2 months from SS. Primary cancer were lung 34, breast 10, and other 10. Fourteen of 54 lesions (26%) developed local recurrence. Leptomeningeal dissemination occurred after the SS in 3 patients (5.7%). RPA classification (1 vs 3, HR:0.16, 95%CI: 0.03–0.59) (2 vs 3, HR:0.44, 95%CI:0.19–0.97) and primary cancer (breast vs lung, HR:0.21, 95%CI:0.05–0.64) (breast vs others, HR:0.08, 95%CI:0.015–0.32) (lung vs others, HR:0.38, 95%CI:0.16–0.94)) were identified as good prognostic factors of overall survival in multivariate analysis. The optimum NLR threshold value was identified as 3.65 for 1-year survival from SS (AUC0.62, sensitivity:71%). CONCLUSIONS: Salvage surgery for local progression of brain metastases after STI in selected cases leads to a meaningful improvement in survival.