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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.