A novel systemic immune-inflammation index predicts survival and quality of life of patients after curative resection for esophageal squamous cell carcinoma

A novel systemic immune-inflammation index (SII) based on platelet (P), neutrophil (N), and lymphocyte (L) counts has been reported to be associated with clinical outcomes in several solid tumors. We aimed to investigate its prognostic value in esophageal squamous cell carcinoma (ESCC) and the potential relationship with quality of life (QOL). A total of 280 ESCC patients who underwent esophagectomy were enrolled. SII (SII = P × N/L) was calculated on the basis of data obtained within 1 week before surgery. An optimal cut-off value stratified patients into high (≥560) and low (<560) preoperative SII groups. The widely used EORTC QLQ-C30 and QLQ-OES18 were utilized to assess QOL at cancer diagnosis and 36 months after surgery. Generalized estimating equations (GEEs) were used to evaluate the association of SII with QOL. Kaplan–Meier method and Cox proportional regression were used to analyze the prognostic value of SII. Kaplan–Meier analyses revealed that higher SII correlated significantly with poorer overall survival (OS) (p < 0.001) and disease-free survival (DFS) (p < 0.001) in patients with ESCC. Multivariate analysis identified SII as an independent prognostic factor for OS (p < 0.001; HR 2.578; 95% CI 1.625–4.088) and DFS (p < 0.001; HR 2.699; 95% CI 1.726–4.223). In addition, patients with high SII exhibited notably deteriorating QOL (p < 0.05). The preoperative SII is a promising biomarker for predicting survival and QOL of patients with ESCC. It may help to identify the high-risk patients for treatment strategy decisions.