Lymph node status after resection for gallbladder adenocarcinoma: Prognostic implications of different nodal staging/scoring systems

Background and Objectives: Several lymph node (LN) staging/scoring systems have been proposed to stratify the prognosis of patients with gallbladder adenocarcinoma (GBA). We sought to define the prognostic performance of the most commonly utilized LN staging/scoring systems including AJCC/UICC N stage, lymph node ratio (LNR), log odds (LODDS), and N score, among patients with GBA. Method: Between 2004 and 2010, 1,124 patients with GBA were identified from the Surveillance Epidemiology and End Results (SEER) database. The discriminative ability of each LN staging/scoring system was assessed using the Akaike's Information Criterion (AIC) and the Harrell's concordance index. Results: When assessed using categorical values, LNR had a modest, improved ability to discriminate patients with regard to prognosis (C-index: 0.615; AIC: 2118.2) compared with AJCC/UICC N stage or N score and a prognostic discrimination comparable to LODDS. Among patients who had a total number of LN examined (TNLE) of 1 or 2, all the staging/scoring systems performed comparably. In contrast, among patients who had ≥4 TNLE, LODDS performed the best (C-index: 0.613; AIC: 303.2). Conclusion: The performance of the different LN staging/scoring systems varied based on the TNLE. In particular, for patients who had ≥ 4 TNLE, LODDS out-performed the other staging/scoring systems.