Preoperative systemic immune-inflammation index predicts prognosis of patients with non-metastatic renal cell carcinoma: a propensity score-matched analysis

BackgroundA novel systemic immune-inflammation index (SII), based on the neutrophils, lymphocytes and platelet counts, is associated with the prognosis of several cancers. The present study evaluates the prognostic significance of SII in non-metastatic renal cell carcinoma (RCC).MethodThe present study retrospectively reviewed the medical record of patients with non-metastatic RCC who underwent nephrectomy between 2010 and 2013. Receiver operating characteristic (ROC) curve analysis was performed to identify the optimal cut-off value. In addition, the propensity score matching (PSM) was performed with a matching ratio of 1:1. Univariate and multivariate Cox proportional hazards models were used to identify the prognostic factors. The results were reported by hazard ratio (HR) with 95% confidence interval (95% CI).ResultsA total of 646 patients were included in the final analysis. High SII group (>529) was significantly associated with older age (P=0.014), larger tumor (P<0.001), higher pathological T stage (P<0.001), higher tumor grade (P<0.001) and more tumor necrosis (P<0.001). Multivariate Cox regression analysis demonstrated that the higher preoperative SII was significantly associated with worse overall survival (OS) (HR=2.26; 95% CI 1.44-3.54; P<0.001) and cancer-specific survival (CSS) (HR=2.17; 95% CI 1.33-3.55; P=0.002). After PSM, elevated preoperative SII was an independent predictor of poor OS (HR=1.78; 95% CI 1.1-2.87; P=0.018) and CSS (HR=1.8; 95% CI 1.07-3.03; P=0.027).ConclusionIn conclusion, preoperative SII is associated with adverse factors for RCC. Furthermore, higher preoperative SII is an independent predictor of poor OS and CSS in surgically treated patients with non-metastatic RCC. More prospective and large scale studies are warranted to validate our findings.