In addition to anectodal observations of the abscopal effect, there are retrospective studies in metastatic non-small cell lung cancer that a Hx of prior RT may improve outcomes of checkpoint inhibitors. A retrospective study by Shaverdian N et al. (Lancet Oncol 2017) found that metastatic non-small cell lung cancer pts who were treated with pembrolizumab (PD-1 inhibitor) who had a Hx of prior RT lived longer than those without prior RT (median OS 10.7 vs. 5.3 mos). Similarly, Hwang WL et al. (JAMA Oncol 2017) found a reduction (NSS) in all-cause mortality in metastatic lung cancer pts treated with PD-1/PD-L1 inhibitors who had a prior Hx of thoracic radiotherapy.