Preoperative increased systemic immune-inflammation index predicts poor prognosis in patients with operable non-small cell lung cancer

Background A novel systemic immune-inflammation index (SII) has been recently reported to be associated with clinical outcome in several tumors. However, the prognostic value of SII has not been reported in operable non small cell lung carcinoma (NSCLC). We aimed to investigate its clinical and prognostic value in patients with operable NSCLC underwent curative surgery. Methods: Four hundred ten NSCLC patients staged I-IIIA were included in this retrospective study. The SII was calculated by the formula: neutrophil x platelet/lymphocyte. Receiver operating characteristic (ROC) curve was used to determine the optimal cut-off value for SII. Kaplan-Meier method and Cox proportional regression were used to analyze the prognostic value of SII. Results: Patients were stratified into high low SII (395.4) and SII (> 395.4) groups. High SII was significantly associated with advanced T stage and positive lymph node metastasis. Kaplan-Meier survival analysis showed that SII, PLR, NLR and LMR were all associated with OS. Multivariate analysis identified that SII was an independent predictor of OS. Furthermore, SII remained prognostic significance for NSCLC patients stratified by TNM subgroups. Conclusions: Preoperative SII was a powerful prognostic biomarker for predicting outcome in patients with operable NSCLC. Preoperative SII may assist clinicians treatment strategy making and individual treatment choice.