Prognostic significance of preoperative systemic immune-inflammation index in combined hepatocellular-cholangiocarcinoma

BACKGROUND: Inflammation-based prognostic scores have been increasingly used for prognosis prediction in malignant tumors. However, no existing study has comprehensively evaluated these scores in combined hepatocellular-cholangiocarcinoma (cHCC-CCA). OBJECTIVE: This study aimed to identify a robust inflammation-based prognostic predictor for cHCC-CCA. METHODS: We retrospectively analyzed 220 patients pathologically confirmed as Allen type C cHCC-CCA. The univariate and multivariate analyses were used to explore the associations between clinical variables and prognosis of cHCC-CCA. The propensity score-matching (PSM) was performed to reduce the effects of potential cofounders and selection bias. Finally, the predictive values of different inflammation-based indices were compared by using time-dependent receiver operating characteristic (ROC) curves. RESULTS: The systemic immune-inflammation index (SII) and aspartate aminotransferase to platelet ratio index (APRI) were identified as independent prognostic predictors in multivariate analysis. After PSM, the survival differences were still significant between SII-high group and SII-low group (P = 0.016 for RFS and P = 0.001 for OS). Further ROC analysis showed that the SII harbored the largest 1-, 3- and 5-year area under the curves (AUC) values as compared with other scores. CONCLUSIONS: The SII may serve as a preferable predictor of both recurrence-free survival (RFS) and overall survival (OS) in patients with cHCC-CCA.