Systemic Effect Of Radiotherapy (Rt) Followed By Programmed Death 1 (Pd-1) Inhibitors In Non-Small-Cell Lung Cancer (Nsclc).

177Background: RT-induced abscopal effect seems increase the efficacy of immunotherapy. The aim of this study was to evaluate the outcome of patients (pts) with NSCLC previously undergone to RT before receiving PD-1 inhibitors. Methods: We conducted an observational, retrospective analysis of 63 consecutive pts with advanced NSCLC who received RT followed by PD-1 inhibitors at five Italian institutions. Tumor response to treatment was defined according to Response Evaluation Criteria in Solid Tumors version 1.1. Median overall survival (OS) and the 95% confidence interval (CI) were estimated with the Kaplan -Meier method. Results: 63 pts (median age 66 years; male:60.3%) with advanced NSCLC (adenocarcinoma [adc]:71.4%; squamous cells [sqc]:28.6%) were treated with PD-1 inhibitors after RT. RT was delivered a median of 70 days before the start of immunotherapy.47 pts(74.5%)received extracranical RT and 16 pts (25.7%) performed cranial irradiation. Median OS was 11.7 months (mo) [95% CI, 4.7-18.7] (adc: 13....