Does the extent of lymphadenectomy, number of lymph nodes, positive lymph node ratio and neutrophil-lymphocyte ratio impact surgical outcome of perihilar cholangiocarcinoma?

Background: Lymph node (LN) status is an important predictor of survival following resection of perihilar cholangiocarcinoma (PHCCA). Controversies still exist with regard to the prognostic value of optimum extent of lymphadenectomy, total number of nodes removed, LN ratio (LNR) and neutrophil-lymphocyte ratio (NLR) on overall survival (OS) and disease-free survival (DFS) following PHCCA resection.

Methods: From 1994 to 2010, 84 PHCCAs were resected; 78 are included in this analysis. Kaplan-Meier survival curves were studied using log-rank statistics to assess which variables affected OS and DFS. The variables that showed statistical significance (P<0.05) on Kaplan-Meier univariate analysis were subjected to multivariate analysis using Cox proportional hazards model.

Results: Five-year OS for node-positive status (n=45) was 10%, whereas node-negative (n=33) OS was 41% (P<0.001). Similarly, 5-year DFS was worse in the node-positive group (8%) than in the node-negative group (36%, P=0.001). There was no difference in 5-year OS (31 vs. 12%, P=0.135) and DFS (22 vs. 16%, P=0.518) between those with regional lymphadenectomy and those who underwent regional plus para-aortic lymphadenectomy, respectively. On univariate analysis, patients with 20 or more LNs removed had worse 5-year OS (0%) when compared with those with less than 20 LNs removed (29%, P=0.047). Moderate/poor tumour differentiation, distant metastasis and LN involvement were independent predictors of OS. Positive LNR had no effect on OS. Vascular invasion and an LNR of at least 0.37 were independent predictors of DFS. NLR had no effect on OS and DFS.

Conclusion: Extended lymphadenectomy patients (≥20 LNs) had worse OS when compared with those with more limited (<20 LNs) resection. An LNR of at least 0.37 is an independent predictor of DFS.