Clinical implication of tumor site in terms of node metastasis for intrahepatic cholangiocarcinoma

Background: The clinical implication of lymph node (LN) dissection of intrahepatic cholangiocarcinoma (ICCA) is still controversial, and LN metastasis (LNM) based on tumor site has not been confirmed yet. Methods: Patients who underwent curative-intent surgery at 10 tertiary referral centers were identified and divided into peripheral (PP) and near second confluence level tumor (NC) groups on the basis of the distance from the second confluence and oncological outcomes were compared. Results: Of 179 patients, 121 patients with LND were divided into the NC (n = 89) and PP groups (n = 32) on the basis of 4.5 cm from the second confluence. NC group showed higher LNM rate than PP group (46.1 vs 21.9%, p = 0.016) and NC was a risk factor for LNM (odds ratio: 4.367; 95% confidence interval: 1.234–15.453, p = 0.022). The 5-year overall survival (OS) rate (38.0% vs. 27.8%, p = 0.777) and recurrence-free survival (RFS) rates (22.8% vs. 25.8%, p = 0.742) showed no differences between the PP and NC groups. In the NC group, N1 patients showed worse 5-year OS (12.7% vs 39.0%, p = 0.004) and RFS (8.8% vs 28.6%, p = 0.004) than the N0 patients. In the PP group, discordant results in 5-year OS (48.9% vs. 50.0%, p = 0.462) and RFS (41.3% vs. 0%, p = 0.056) were found between the N0 and N1 patients. Conclusion: The NC group was an independent risk factor for LNM and LNM worsened prognosis in NC group for ICCA. In the PP group, LND should not be omitted because of high LNM rate and insufficient oncologic evidence.