Lymph nodal involvement as prognostic factor in gallbladder cancer: location, count or ratio?

BACKGROUND: Lymph nodal involvement is a critical prognostic factor in patients with gallbladder cancer (GBC). Controversy exists regarding optimal categorization of nodal status, and no study has investigated the relevance of metastatic to examined nodes ratio (LNR) in these patients.

METHODS: Demographic, operative and pathologic data including total lymph node count (TLNC), positive lymph node count (PLNC), LNR and involved nodal location was recorded in 57 patients with GBC who underwent curative intent resection. Disease-free survival (DFS) and predictors of outcome were analyzed.

RESULTS: At a median follow-up of 19 (i.q.r: 11-39.5) months, median DFS was 28.25 ± 3.62 months and 35 (61%) patients had developed recurrence. Thirty-three (58%) patients had nodal involvement, and a linear correlation was observed between TLNC and PLNC (r (2) = 0.249, p < 0.001). Optimal TLNC and LNR were determined to be 6 and 0.50, respectively. Patients with negative nodes (N0) were better sub-stratified based on TLNC (median DFS, TLNC ≥ 6 vs. TLNC < 6: not reached vs. 32.00 ± 4.80 months, p = 0.012). Amongst patients with involved nodes, LNR was significantly associated with DFS (median DFS, 0 < LNR ≤ 0.50 vs. LNR > 0.50: 14.00 ± 2.46 vs. 9.00 ± 1.55 months, p < 0.001). Prognosis was not related to location of involved nodes. Multivariable analysis revealed T stage, tumor differentiation and LNR to be independent predictors of DFS.

CONCLUSIONS: LNR is a strong predictor of outcome after curative resection for GBC. The retrieval and examination of at least 6 nodes can influence staging quality and DFS in node-negative patients.