ABSTRACT
Objective:To investigate whether radiotherapy should be delivered before the application of immune checkpoint inhibitor PD-1 in patients with advanced non-small cell lung cancer (NSCLC) and evaluate the effect of previous radiotherapy on the efficacy and pulmonary toxicity of PD-1 inhibitor.Methods:Clinical data of patients with stage Ⅳ NSCLC who received immunotherapy in Henan Cancer Hospital from March 2015 to September 2019 were retrospectively analyzed. The baseline data of patients, the status of radiotherapy and immunotherapy and the pulmonary toxicity were collected. According to whether radiotherapy was given before PD-1 inhibitor application, all patients were divided into the previous radiotherapy and non-radiotherapy groups. Survival analysis was performed by Kaplan- Meier method. Results:A total of 90 patients were enrolled including 39 cases in the previous radiotherapy group and 51 cases in the non-radiotherapy group. The median follow-up time was 22.9 months. The median progression-free survival (mPFS) in the previous radiotherapy group was 7.5 months (95% CI 5.4-9.5 months), significantly longer compared with 4.1 months (95% CI 3.1-5.1 months) in the non-radiotherapy group ( P=0.003). The median overall survival (mOS) significantly differed between two groups[15.2 months (95% CI 12.3-18.1 months) vs. 9.3 months (95% CI 6.1-12.5 months)]( P=0.040). The incidence of pulmonary toxicity showed no significant difference between two groups ( P=0.154). Conclusions:Patients with stage Ⅳ NSCLC patients in the previous radiotherapy group obtain significantly better mPFS and mOS and similar pulmonary toxicity compared with their counterparts in the non-radiotherapy group. Nevertheless, the findings remain to be validated by subsequent investigations with larger sample size.