Repeat stereotactic radiosurgery for locally recurrent brain metastases previously treated with stereotactic radiosurgery: A systematic review and meta-analysis of efficacy and safety

Objectives: To perform a systematic review and meta-analysis of outcomes for patients with locally recurrent brain metastases treated with a repeat course of stereotactic radiosurgery (rSRS). Method: Primary outcomes were 1-year local control(LC) and radionecrosis (RN). Secondary outcomes were 1-year overall survival (OS) and 1-year distant brain control (DBC). Weighted random effects meta-analyses utilizing the DerSimonian and Laird methods were conducted to characterize summary effect sizes. Mixed effects regression models were utilized to analyze potential correlations between prognostic factors and outcomes. Results: In total, 347 patients with 462 brain metastases treated with rSRS were included. Estimated 1-year LC, OS, and DBC rates were 69.0% (95% CI: 61.0-77.0%), 49.7% (95% CI: 28.9-70.6%), and 41.6% (95% CI: 33.0-50.4%), respectively. The estimated RN rate was 16.1% (95% CI: 6.3-25.9%). Every 1 Gy increase in prescription dose was estimated to result in roughly 5% increase in 1-year LC (p = 0.14). Conclusions: rSRS was well-tolerated with reasonable 1-year LC and OS. Dose escalation may result in improved LC.