Application value of different lymph node staging system in predicting prognosis of patients with intrahepatic cholangiocarcinoma

Objective: To examine the value of number of metastatic lymph nodes(NMLN), lymph node ratio(LNR) and log odds of metastatic lymph nodes(LODDS) in assessing the prognosis of patients with intrahepatic cholangiocarcinoma(ICC). Methods: The clinical and pathological data of 440 ICC patients who underwent curative-intent resection in 10 of Chinese hepatobiliary surgery centers from January 2010 to December 2018 were collected, and the deadline of follow-up was April 30th, 2019. Among them, 205 were males and 235 were females, with age of (57.0+/-9.9) years (range:23-83 years).Eighty-five cases (19.3%) had intrahepatic bile duct stones, and 98 cases (22.3%) had chronic viral hepatitis.The Kaplan-Meier method was used for survival analysis. The univariate and multivariate analysis were implemented respectively using the Log-rank test and Cox proportional hazard model. Results: A total of 440 patients underwent curative-intent resection and lymphadenectomy.R0 resection were achieved in 424 cases (96.4%) and R1 resection were in 16 cases (3.6%). The results of postoperative pathological examination showed that high, moderate and poor differentiation was 4.2%(18/426), 60.6%(258/426) and 35.2%(150/426), respectively.Adenocarcinoma was seen in 90.2%(397/440) and non-adenocarcinoma was seen in 9.8%(43/440), respectively. T stage: 2 cases (0.5%) with Tis, 83 cases(18.9%) with T1a, 97 cases(22.0%) with T1b, 95 cases(21.6%) with T2, 122 cases (27.7%) with T3 and 41 cases(9.3%) with T4.The overall median survival time was 24.0 months, and the 1-,3-, and 5-year survival rate was 74.3%, 37.7% and 18.3%, respectively. Lymphatic metastasis occurred in 175 patients(39.8%), the median total number of TNLE(M(Q(R))) was 6(5), the median number of NMLN was 0(1), the median number of LNR was 0 (0.33) and the median number of LODDS was -0.70(-0.92). Rerults of univariate analysis showed that combined stones, pathological differentiation, vascular invasion, LODDS, margin and T staging affected the prognosis (all P<0.05). Rerults of multivariate analysis showed that pathological differentiation, LODDS, margin, and T staging were independent risk factors affecting the prognosis of ICC patients (all P<0.05). Conclusion: LODDS could be used as an optimal prognostic lymph node staging index for ICC, and it is also an independent risk factor for survival after curative intent resection.