Abstract: Background and purpose: Intrahepatic cholangiocarcinoma (ICC) is the second most common pathological type of primary liver cancer. It has insidious onset and poor prognosis. Lymph node metastasis (LNM) is common in ICC. This study aimed to identify the relationship between LNM and clinical parameters and prognosis in patients with ICC after curative resection. Methods: A total of 322 patients with ICC who underwent a curative hepatic resection in Zhongshan Hospital, Fudan University were enrolled in this study. Clinicopathological parameters including LNM and serum CA19-9 were analyzed for long-term survival outcomes. Results: LNM was significantly correlated with hepatitis B virus (HBV) infection, preoperative serum CA19-9, tumor number, diameter of largest tumor nodule, microvascular invasion, TNM staging and neutrophil-to-lymphocyte ratio (NLR). Kaplan-Meier curve was applied to evaluate the clinicopathological parameters and prognosis. The 1-, 3-, and 5-year overall survival (OS) rates were 80.8%, 53.4% and 40.3%, respectively in LNM (-) group, significantly better compared with LNM (+) group (P<0.001) (47.4 %, 20.4 % and 10.2%, respectively). The 1-, 3-, and 5-year recurrence-free survival (RFS) rates were 62.6%, 43.4% and 36.3%, respectively in LNM (-) group, significantly better compared with LNM (+) group (P<0.001) (25.6 %, 16.6% and 12.4%, respectively). We found preoperative serum CA19-9 >89 U/mL (P<0.001), diameter of largest tumor nodule greater than 5cm (P=0.042), multiple tumor (P<0.001), micro vascular invasion (P=0.022), advanced TNM stage (P<0.001), NLR≥2.49 (P=0.016), lymphocyte-to-monocyte ratio (LMR)<4.45 (P=0.048) and LNM (P<0.001) had adverse impact on time to recurrence (TTR). As well, preoperative serum CA19-9>89 U/mL (P<0.001), diameter of largest tumor nodule greater than 5 cm (P=0.008), multiple tumor (P=0.002), advanced TNM stage (P<0.001), NLR≥2.49 (P<0.001), LMR<4.45 (P=0.002) and LNM (P<0.001) were negatively correlated with OS. Cox regression model indicated preoperative serum CA19-9>89 U/mL, multiple tumor, LNM were independent prognostic factors for TTR. Preoperative serum CA19-9>89 U/mL, multiple tumor, LMR<4.45, LNM were independent prognostic factors for OS of ICC patients. Conclusion: Hepatoduodenal ligament LNM is an independent prognostic factor of ICC patients after curative resection. It has important prognostic value to increase the detection rate of LNM.

Key words: Intrahepatic cholangiocarcinoma, Curative resection, Lymph node metastasis, Prognosis