A multicenter retrospective study on clinical value of lymph node dissection in the radical resection of intrahepatic cholangiocarcinoma

Objective To investigate the clinical value of lymph node dissection (LND) in the radical resection of intrahepatic cholangiocarcinoma (ICC). Methods The propensity score matching and retrospective cohort study was conducted. The clinicopathological data of 448 patients with ICC who were admitted to 12 medical centers from December 2011 to December 2017 were collected, including 279 in the Eastern Hepatobiliary Surgery Hospital of Navy Medical University, 32 in the Mengchao Hepatobiliary Hospital of Fujian Medical University, 21 in the First Hospital Affiliated to Army Medical University, 20 in the Cancer Hospital Chinese Academy of Medical Science and Peking Union Medical College, 19 in the West China Hospital of Sichuan University, 18 in the Second Hospital Affiliated to Zhejiang University School of Medicine, 18 in the Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine, 16 in the Beijing Friendship Hospital Affiliated to Capital Medical University, 10 in the Xuanwu Hospital Affiliated to Capital Medical University, 7 in the Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology, 5 in the Beijing Tiantan Hospital Affiliated to Capital Medical University, and 3 in the Affiliated Hospital of North Sichuan Medical College. There were 281 males and 167 females, aged from 22 to 80 years, with a median age of 57 years. Of the 448 patients, 143 with routinely intraoperative LND were divided into LND group and 305 without routinely intraoperative LND were divided into control group, respectively. Observation indicators: (1) the propensity score matching conditions and comparison of general data between the two groups after matching; (2) intraoperative and postoperative situations; (3) follow-up; (4) survival analysis. Patients were followed up by outpatient examination, telephone interview and email to detect survival of patients and tumor recurrence up to October 31, 2018 or death. Follow-up was conducted once every 3 months within postoperative 1-2 years, once every 6 months within postoperative 2-5 years, and once a year after 5 years. The propensity score matching was realized using the nearest neighbor method with 1∶1 ratio. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was analyzed using the t test. Measurement data with skewed distribution were represented as M (range), and comparison between groups was analyzed using the Mann-Whitney U test. Count data were described as absolute numbers, and comparison between groups was analyzed using the chi-square test or Fisher exact probability. Kaplan-Meier method was used to calculate survival rates and draw survival curve, and Log-rank test was used to perform survival analysis. Univariate analysis and multivaraiate analysis were conducted using the Log-rank test and COX regression model, respectively. Results (1) The propensity score matching conditions and comparison of general data between the two groups after matching: 286 of 448 patients had successful matching, including 143 in each group. The number of males and females, cases with hepatitis, cases with grade A and B of Child-Pugh classification, cases with distance from margin to tumor 0.05). (2) Intraoperative and postoperative situations: the operation time, volume of intraoperative blood loss, cases with intraoperative blood transfusion, cases with postoperative complications, and duration of postoperative hospital stay were 265 minutes (range, 160-371 minutes), 300 mL (range, 200-500 mL), 37, 46, 12 days (range, 9-17 days) for the LND group, and 59 minutes (range, 46-250 minutes), 200 mL (range, 100-400 mL), 24, 25, 9 days (range, 7-11 days) for the control group, respectively. There was no significant difference in the volume of intraoperative blood loss or cases with intraoperative blood transfusion between the two groups (Z=1.700, χ2=3.520, P>0.05). There were significant differences in the operation time, cases with postoperative complications, and duration of postoperative hospital stay (Z=6.520, χ2=8.260, Z=4.270, P 0.05). (4) Survival analysis: results of univariate analysis showed that distance from margin to tumor, tumor diameter, the number of tumors, microvascular tumor thrombus, and lymph node metastasis by pathological examination were related factors for prognosis of patients undergoing radical resection of ICC (χ2=10.662, 9.477, 16.944, 6.520, 11.633, P 5 cm, multiple tumors, microvascular tumor thrombus, positive lymph node metastasis by pathological examination were independent risk factors for prognosis of patients undergoing radical resection of ICC (hazard ratio=0.600, 1.571, 1.601, 1.750, 1.723, 95% confidence interval: 0.430-0.837, 1.106-2.232, 1.115-2.299, 1.083-2.829, 1.207-2.460, P<0.05). Conclusion Lymph node metastasis is an independent risk factor affecting the prognosis of ICC patients, and it is necessary to perform LND in radical resection for patients with ICC and lymph node metastasis. Key words: Bile duct neoplasms; Intrahepatic cholangiocarcinoma; Radical resection; Lymph node dissection; Prognosis; Multicenter; Retrospective