Postchemoradiotherapy systemic inflammation response index predicts treatment response and overall survival for patients with locally advanced nasopharyngeal cancer

To explore the clinical utility of the systemic inflammation response index (SIRI) in the prediction of patients with poor treatment response to concurrent chemoradiotherapy (CCRT) in locally advanced nasopharyngeal cancer (NPC). A total of 167 stage III-IVB (AJCC 7th edition) nasopharyngeal cancer patients who received CCRT were retrospectively collected. The SIRI was calculated using the following formula: SIRI = neutrophil count × monocyte count/lymphocyte count (109/L). The optimal cutoff values of the SIRI for noncomplete response were determined by receiver operating characteristic curve analysis. Logistic regression analyses were performed to identify factors predictive of treatment response. We used Cox proportional hazards models to identify predictors of survival. Multivariate logistic regression showed that only the posttreatment SIRI was independently associated with treatment response in locally advanced NPC. A posttreatment SIRI≥1.15 was a risk factor for developing an incomplete response after CCRT (odds ratio 3.10, 95% confidence interval (CI): 1.22-9.08, p=0.025). A posttreatment SIRI≥1.15 was also an independent negative predictor of progression-free survival (hazard ratio 2.38, 95% CI: 1.35-4.20, p=0.003) and overall survival (hazard ratio 2.13, 95% CI: 1.15-3.96, p=0.017). The posttreatment SIRI could be used to predict the treatment response and prognosis of locally advanced NPC.