Prognostic significance of systemic immune-inflammation index in patients with intrahepatic cholangiocarcinoma undergoing hepatic resection

BACKGROUND The prognosis of intrahepatic cholangiocarcinoma (ICC) patients following surgical resection remains poor. It is necessary to investigate effective biomarkers or prognostic models for ICC patients. AIM To investigate the prognostic effect of systemic immune-inflammation index (SII) to predict long-term outcomes in ICC patients with undergoing hepatic resection. METHODS Consecutive ICC patients who underwent initial hepatectomy with curative intent from January 2009 to September 2017 were retrospectively reviewed. Receiver-operating characteristic (ROC) curves were used to determine the optimal cut-off values of SII. Kaplan-Meier curves and Cox proportional hazards regression were performed to evaluate the discriminative ability of preoperative SII in predicting overall survival (OS) and recurrence-free survival (RFS). RESULTS A total of 530 patients were included and randomly divided into derivation (n = 265) and validation cohort (n = 265). The optimal cut-off value for SII was 450. At a median follow-up of 18 mo (range, 1-115.4 mo), 317 (59.8%) patients died and 381 (71.9%) patients experienced tumor relapse. Low SII level was associated with better OS and RFS (both P < 0.05). Multivariate analyses identified multiple tumors, node invasion and high SII level as independent risk factors for OS, while multiple tumors, node invasion and high SII level were identified as independent risk factors for RFS. Validation cohort confirmed the findings of derivation cohort. CONCLUSION The present study demonstrated the feasibility of preoperative SII as a prognostic indicator for ICC. Patients with increased SII level were associated with worse OS and earlier tumor recurrence. Elevated SII level was an independent risk factor for OS and RFS in patients with ICC after hepatectomy. In the future, the SII could help stratifying patients with ICC, thus guiding therapeutic choices, especially in immunotherapy.