The predict factors and clinical prognosis value of immune-related pneumonia of receiving PD-1 inhibitor in advanced non-small cell lung cancer: A retrospective study

Introduction Immune checkpoint inhibitor-associated pneumonitis (CIP) is the most common immune-related advanced event (irAE). However, the risk factors of CIP occurrence and its relationship with prognosis remain to be clarified. This study aimed to explore biomarkers, prognosis, and efficacy of CIP occurrence in non-small cell lung cancer (NSCLC) patients who received anti-PD-1 inhibitors. Methods We performed a retrospective study in eligible NSCLC patients treated with anti-PD-1 inhibitors in Ruijin hospital. The receiver operating characteristic (ROC) curve and logistic regression were used for the optional cut-off value and the risk of CIP, respectively. The Kaplan-Meier method and Cox hazards regression models were used for survival analyses in CIP and non-CIP groups. Results Our study enrolled 229 patients, of which 35 (15.3 %) experienced CIP. CIP patients had higher proportions of male, current and former smoking, and history of pre-existing lung diseases. CIP patients also had a higher level of WBC (p = 0.025), ANC (p = 0.020), AEC (p = 0.025), and proportion of CD4(+) T lymphocytes (p = 0.033) than those in non-CIP patients. Then patients were divided into two groups according to the cutoff value. It showed high baseline proportion of CD4(+) T lymphocytes (OR = 4.027 (1.279-12.677), P = 0.017) and AEC (OR = 2.697 (1.047-6.945, P = 0.040) were independent predictors of CIP occurrence. CIP occurrence was an independent predictor of progression-free survival (PFS) in the enrolled patients. Regarding patient efficacy, severe-CIP patients had the highest ORR, followed by grade 1-2 CIP patients, and non-CIP patients (44.44 %, 35.3 %, and 28.35 %, respectively). Conclusion The onset time of CIP occurrence was early in severe CIP patients, suggesting the importance of early identification and timely intervention of CIP. Baseline proportion of CD4(+) T lymphocytes and AEC were independent predictors of CIP occurrence. In addition, CIP occurrence predicted higher ORR, longer PFS, and more opportunities for long-term survival benefits.