Extent of Lymph Node Dissection for Accurate Staging in Intrahepatic Cholangiocarcinoma

Background Although lymph node metastasis is a known factor predictive of a poor prognosis after radical surgery for intrahepatic cholangiocarcinoma (ICC), few studies have investigated lymph node dissection (LND) areas for accurate staging. The aim of this study was to identify the optimal LND level for ICC considering lymphatic flow. Methods Clinical characteristics and pathologic nodal status (presence of metastasis) for 163 patients were reviewed according to tumor location. In the node-positive (N1) group, the distribution of metastatic nodes was described. The coverage of metastatic nodes according to dissection level was assessed, and the minimum dissection level for accurate ICC staging was estimated accordingly. For validation, the node-negative (N0) group was divided into two subgroups according to the estimated dissection level, and survival outcomes were compared. Results In the N1 group, expanding dissection to stations no. 12 and 8 covered 82.0% (n = 50) of metastatic cases regardless of tumor location. In survival analysis of N0 group, patients who underwent LND covering stations no. 8+12 showed better disease-free survival (DFS) and overall survival (OS), although the differences were not statistically significant (DFS: covering no. 12+8 vs. not covering no. 12+8, 109.0 months [24.2-193.8] vs. 33.0 months [10.3-55.7], p = 0.078; OS: covering no. 12+8 vs. not covering no. 12+8, 180.0 months [21.6-338.4] vs. 73.0 months [42.8-103.2], p = 0.080). Conclusion LND including at least stations no. 12 (hepatoduodenal ligament) and 8 (common hepatic artery), regardless of tumor location, is recommended for accurate staging in ICC patients.