The efficacy and safety of immunotherapy and palliative radiotherapy in metastatic non-small cell lung cancer patients: a systematic review and meta-analysis

Objective: Palliative radiotherapy (pRT) is usually used in the treatment of metastatic non-small cell lung cancer (mNSCLC). However, whether pRT could influence the outcomes of mNSCLC patients who considered immune checkpoint inhibitors (ICIs) as maintenance treatment is still under debate. Here we did a systematic review and meta-analysis to assess the efficacy and safety of this combination strategy in mNSCLC patients. Methods: : The PubMed, Cochrane and Embase databases were searched for prospective studies and randomized controlled trials (RCTs). The main outcomes were overall survival (OS), progression-free survival (PFS), disease control rate (DCR), objective response rate (ORR), and treatment-related adverse events. All data was analyzed with Stata v 16.0 and Review Manager version 5.4 software. Results: : A total of 12 studies were included. pRT plus ICIs was significantly associated with improved DCR (OR=2.27, 95%CI [1.27, 4.04]; p =0.008), OS (HR=0.66, CI [0.54, 0.80]; p <0.0001) and PFS (HR=0.60, CI [0.44, 0.81]; p =0.0009). In safety analyses of III-IV grade adverse events (AEs), patients receiving ICIs plus pRT showed no statistically significant difference ( p =0.43) when compared with those in the control group. Conclusion: Patients with mNSCLC may benefit from the ICI and pRT combination therapy with acceptable incidence of grade III-IV AEs.