Systemic inflammatory response index is a prognostic biomarker in unresectable pancreatic adenocarcinoma and identifies patients for more intensive treatment

Summary Background The link between systemic inflammation and pancreatic cancer is widely accepted. The systemic inflammatory response index (SIRI), based on peripheral neutrophil, monocyte, and lymphocyte counts, emerged recently as a prognostic tool in several types of cancer. The aim of this study is to evaluate the prognostic and predictive value of baseline SIRI in unresectable pancreatic cancer. Materials and methods Retrospective analysis of 112 patients with unresectable pancreatic ductal adenocarcinoma (PDAC) followed between 2016 and 2021. Receiver operating characteristic (ROC) curve analysis was used to obtain the optimal SIRI cut-off value, which was set at 1.34. Results Univariate analysis showed that SIRI ≥ 1.34 was associated with significantly lower overall survival (OS; p < 0.0001). Multivariate analyses confirmed that SIRI is an independent prognostic factor regardless of first-line chemotherapy regimen ( p < 0.0001; hazard ratio [HR] 0.363; 95% confidence interval [CI] 0.223–0.566). Also, patients with SIRI ≥ 1.34 undergoing platinum-based treatment had significantly longer OS than those treated with gemcitabine-based regimens ( p = 0.002). Conclusion Our study suggests that SIRI is able to predict OS in patients with PDAC. Patients with high SIRI values treated with platinum-based chemotherapy achieved longer OS than those treated with gemcitabine-based regimens.