INTRODUCTION : Despite lymph node metastases (LNMs) being associated with worse survival, adequate lymph node evaluation (LNE) has not been universally adopted for intrahepatic cholangiocarcinoma (ICC). We sought to evaluate trends in LNE, predictors of LNE and LNM, as well as the role of adequate lymphadenectomy in stratifying patients relative to survival.

METHODS : Patients who underwent curative-intent liver resection for ICC (2010-2019) were identified from the National Cancer Database and stratified according to LNE: 0, 1-5 (inadequate lymphadenectomy) and ≥6 (adequate lymphadenectomy). Multivariate logistic regression was utilized to assess predictors of LNE and LNM. Overall survival and receipt of adequate lymphadenectomy were assessed relative to LNM and log-odds of lymph nodes (LODDS).

RESULTS : Among 6507 patients, adequate lymphadenectomy was performed in only 1118 (17.2%) patients, although compliance with adequate lymphadenectomy increased over time (2010-2012: 14.2% vs. 2016-2019: 18.9%; p < 0.001). After controlling for relevant factors, region (reference: Northeast; Midwest: odds ratio [OR] 1.90, 95% confidence interval [CI] 1.48-2.44; South: OR 1.64, 95% CI 1.28-2.10; West: OR 1.83, 95% CI 1.37-2.44) and preoperative nodal status (reference: cN0; cNx: OR 2.18, 95% CI 1.68-2.95; cN1: OR 3.88, 95% CI 3.02-4.98) strongly predicted adequate lymphadenectomy. Furthermore, adequate lymphadenectomy resulted in higher odds of detecting ≥1 LNMs (OR 2.63, 95% CI 2.25-3.08), regardless of preoperative nodal status. Adequate lymphadenectomy demonstrated an improved ability to stratify patients relative to 5-year survival based on LNM (N0: 51.3% vs. N1: 30.6% vs. N2: 13.7%; p < 0.001) and LODDS (LODDS1: 50.7% vs. LODDS2: 27.4% vs. LODDS3: 15.7%; p < 0.001).

CONCLUSIONS : Compliance with adequate lymphadenectomy at the time of surgery for ICC remains suboptimal with marked regional variations. Adequate lymphadenectomy was associated with higher odds of detecting LNM and improved survival stratification relative to both LNM and LODDS. Greater emphasis on nodal evaluation is required to ensure optimal management of ICC.