Oncological impacts of lymph node dissection in intrahepatic cholangiocarcinoma with preoperative radiologically negative lymph node metastasis

Backgrounds/Aims:The oncological benefit of lymph node dissection (LND) in intrahepatic cholangiocarcinoma (iCCA) without radiological evidence of nodal metastasis remains uncertain.We evaluated the impact of LND on survival in patients with clinically node-negative (cN0) iCCA.Methods: We retrospectively reviewed 278 patients who underwent curative-intent hepatic resection for iCCA between January 2013 and February 2020.Among 131 patients with cN0 disease, 57 underwent LND and 74 did not.The use of LND was largely determined by the operating surgical division.After 1:1 propensity score matching, clinicopathologic characteristics, perioperative outcomes, and survival were compared.Covariate balance was assessed using standardized mean differences (SMDs), and residual imbalance was addressed using covariate-adjusted Cox regression and inverse probability of treatment weighting (IPTW).Results: After matching (n = 70), most covariates were balanced; however, imbalances remained in the extent of hepatectomy (SMD, 0.85) and tumor growth pattern (SMD, 0.61).Postoperative morbidity and hospital stay were similar between groups.Three-year overall survival (47.6% vs. 61.2%)and recurrence-free survival (47.3% vs. 54.3%)did not differ significantly between the LND and non-LND groups (both p > 0.05).These findings were consistent in covariate-adjusted and IPTW analyses.American Joint Committee on Cancer stage and preoperative CA 19-9, but not LND, were independent prognostic factors.Conclusions: LND was not associated with a significant survival benefit in patients with cN0 iCCA.However, its therapeutic value remains inconclusive because treatment allocation was related to operative practice and the number of patients with pathologically positive nodes may have been limited.