Hypofractionated radiation therapy with versus without immune checkpoint inhibitors in patients with brain metastases: A meta-analysis

Abstract

IntroductionThe efficacy and safety of hypofractionated radiation therapy (HFRT) combined with immune checkpoint inhibitors (ICIs) in patients with brain metastases (BM) remain controversial. This meta-analysis was performed to compare the efficacy and safety of HFRT with and without ICIs in BM patients. Materials and MethodsPubMed, Embase, and Cochrane Library were searched up to 25 December 2018 for studies that compared the efficacy and safety of HFRT with and without ICIs in BM patients. ResultsTwenty-four studies involving 2,365 patients were included in this analysis. Compared with those of HFRT without ICIs, the 6-month locoregional recurrence-free survival (LRFS) rate (P = 0.002), 6-month overall survival (OS) rate (P = 0.001), 1-year OS rate (P = 0.001), 2-year OS rate (P = 0.007), and median OS (mOS) (P < 0.001) were significantly improved in combined HFRT and ICI treatment. A trend toward improved 1-year LRFS rate (P = 0.392) and 3-year OS rate (P = 0.266) for the ICI arm was observed compared with the non-ICI arm, although there was no statistically significant difference between the two arms. No significant difference in toxicity was found between the two arms (radionecrosis: P = 0.361; BM hemorrhage: P = 0.738). ConclusionsCompared with HFRT without ICIs, the combination of these two therapies improved efficacy but did not increase toxicity in patients with BM.