Theelen WSME, Peulen HMU, Lalezari F, et al. - Through a phase 2 clinical trial of 76 patients with recurrent metastatic non–small cell lung cancer (NSCLC) randomized to either pembrolizumab alone or pembrolizumab following stereotactic body radiotherapy on a single tumor site, researchers evaluated whether stereotactic body radiotherapy on a single tumor site preceding pembrolizumab treatment improved tumor response in individuals with metastatic NSCLC. A total of 76 were randomly allocated to the control arm (n = 40) or the experimental arm (n = 36). Subgroup analyses revealed the biggest advantage from the addition of radiotherapy in patients with PD-L1–negative tumors. No progress in treatment-related toxic impacts was seen in the experimental arm. In conclusion, stereotactic body radiotherapy former to pembrolizumab was well tolerated. However a doubling of overall response rate was noted, the results could not meet the study’s prespecified endpoint criteria for significant clinical advantage. Positive results were principally affected by the PD-L1–negative subgroup, which had significantly enhanced progression-free survival and overall survival.