Clinical implications and optimal extent of lymphadenectomy for intrahepatic cholangiocarcinoma: A multicenter analysis of the therapeutic index

AIMS: Lymph node metastases (LNM) are associated with lethal prognosis in intrahepatic cholangiocarcinoma (ICC). Lymphadenectomy is crucial for accurate staging and hopes of possible oncological treatment. However, the therapeutic implications and optimal extent of lymphadenectomy remain contentious. METHODS: To clarify the prognostic value and optimal extent of lymphadenectomy, the therapeutic index (TI) for each lymph node was analyzed for 279 cases that had undergone lymphadenectomy in a multi‐institutional database. Tumor localization was divided into hilar lesions (n = 130), right peripheral lesions (n = 60), and left peripheral lesions (n = 89). In addition, the lymph node station was classified as Level 1 (LV1: hepatoduodenal ligament node), Level 2 (LV2: postpancreatic or common hepatic artery nodes), or Level 3 (LV3: gastrocardiac, left gastric artery, or celiac artery nodes). RESULTS: Lymph node metastases were confirmed in 109 patients (39%). Five‐y survival rates were 45.3% for N0 disease, 27.1% for LV1‐LNM, 22.9% for LV2‐LNM, and 7.3% for LV3‐LNM (P < 0.001). LV3‐LNM were the most frequent and earliest recurrence outcome, including multisite recurrence, followed by LV2, LV1, and N0 disease. The 5‐year TI (5year‐TI) for lymphadenectomy was 7.2 for LV1, 5.5 for LV2, and 1.9 for LV3. Regarding tumor location, hilar lesions showed 5‐year TI >5.0 in LV1 and LV2, whereas bilateral peripheral lesions showed 5‐year TI > 5.0 in LV1. CONCLUSION: The implications and extent of lymphadenectomy for ICC appear to rely on tumor location. In the peripheral type, the benefit of lymphadenectomy would be limited and dissection beyond LV1 should be avoided, while in the hilar type, lymphadenectomy up to LV2 could be recommended.