Predictive Value of Neutrophil-to-Lymphocyte Ratio for Immune Checkpoint Inhibitor-Related Myocarditis Among Patients Treated for Non-Small-Cell Lung Cancer.

Background: The predictive value of the neutrophil-to-lymphocyte ratio (NLR) for immune checkpoint inhibitors (ICIs) in various tumors remains uncertain despite its use in forecasting the effectiveness of immunotherapy. The purpose of our research was to determine the prognostic significance of NLR for immune checkpoint inhibitor-related myocarditis in non-small-cell lung cancer (NSCLC) patients. Methods: We enrolled and monitored patients with NSCLC who received ICI therapy at the Fifth Medical Center of Chinese PLA General Hospital between January 1, 2018, and February 20, 2021. NLR was determined before and soon after each cycle of ICIs. All participants in this study were periodically examined for troponin and brain natriuretic peptide (BNP), and an electrocardiogram (ECG) and echocardiography were done. Cox's proportional hazards regression model and receiver operating characteristic (ROC) were used to assess the predictive value for ICI-related myocarditis. Results: A total of 146 patients received ICI treatment and completed a follow-up. Of these, 17 patients (11.64%) developed ICI-related myocarditis that met the diagnostic criteria. The initial cycle revealed that the NLR was a reliable predictor of potential myocarditis related to ICIs, with an area under the curve (AUC) of 0.833 and a 95% confidence interval (CI) of 0.721-0.945. Following the initial round of ICI treatment, an NLR elevation (NLR ≥ 3.25) appeared to be the most significant standalone indicator of ICI-related myocarditis (HR: 11.094; 95% CI: 3.186-38.631; Conclusions: Our study confirmed that NLR elevation in the early phase after ICI treatment of NSCLC is a reliable predictive factor of ICI-related myocarditis. Regular and frequent cardiac monitoring may help to avoid the occurrence of severe and fatal cases.