High systemic immune-inflammation index is a predictor of poor prognosis in patients with nonsmall cell lung cancer and bone metastasis

This study aimed to evaluate whether systemic immune inflammation (SII) is correlated with overall survival (OS) in patients with nonsmall cell lung cancer (NSCLC) and bone metastasis.This was a retrospective analysis of the value of pretreatment SII in patients with NSCLC and bone metastasis.Two hundred and thirty-four patients with pathologically confirmed NSCLC and bone metastasis treated at Harbin between January 2008 and May 2010 were included. Baseline clinical characteristics and pretreatment SII were collected for further analysis.Receiver operating characteristic curve analysis was used to calculate the optimal cutoff value for SII. Survival analysis was performed using the Kaplan-Meier method. Factors associated with OS were identified by univariate and multivariate analyses.The optimal cutoff value for pretreatment SII was 618.3 × 109/L. Pretreatment SII ≥618.3 × 109/L was more commonly seen in patients with a greater number of distant metastases (<2 vs. ≥2, 56.4% vs. 70.0%, P = 0.033). Univariate analysis showed that sex, tumor histology, Eastern Cooperative Oncology Group-Performance Status (ECOG-PS) score, pretreatment SII, and systemic chemotherapy were associated with OS (P < 0.05). Multivariate analysis showed that sex (hazard ratio [HR] = 1.349, 95% confidence interval [CI] = 1.029-1.708, P = 0.030), ECOG-PS (HR = 1.674, 95% CI = 1.256-2.232, P < 0.001), SII (HR = 1.456, 95% CI = 1.100-1.927, P = 0.009), and systemic chemotherapy (HR = 0.596, 95% CI = 0.437-0.813, P = 0.001) were independent prognostic factors. Subgroup analyses found that SII was prognostic for patients with the following characteristics: age <65 years (P = 0.002), female (P = 0.021), nonsmoker (P = 0.010), histology of adenocarcinoma (P = 0.022), ECOG-PS <2 (P = 0.013), two or more distant metastases (P = 0.004), and two or more bone metastases (P = 0.009).Pretreatment SII may be a prognostic biomarker for NSCLC and bone metastasis.