Validation of the prognostic performance in various nodal staging systems for gallbladder cancer: results of a multicenter study

Abstract

Background Although the current nodal staging system for gallbladder cancer (GBC) was changed based on the number of positive lymph nodes (PLN), it needs to be evaluated in various situations. Methods We reviewed the clinical data for 398 patients with resected GBC and compared nodal staging systems based on the number of PLNs, the positive/retrieved LN ratio (LNR), and the log odds of positive LN (LODDS). Prognostic performance was evaluated using the C-index. Results Subgroups were formed on the basis of an restricted cubic spline plot as follows: PLN 3 (PLN = 0, 1-2, >= 3); PLN 4 (PLN = 0, 1-3, >= 4); LNR (LNR = 0, 0-0.269, >= 0.27); and LODDS (LODDS < - 0.8, - 0.8-0, >= 0). The oncological outcome differed significantly between subgroups in each system. In all patients with GBC, PLN 4 (C-index 0.730) and PLN 3 (C-index 0.734) were the best prognostic discriminators of survival and recurrence, respectively. However, for retrieved LN (RLN) >= 6, LODDS was the best discriminator for survival (C-index 0.852). Conclusion The nodal staging system based on PLN was the optimal prognostic discriminator in patients with RLN < 6, whereas the LODDS system is adequate for RLN >= 6. The following nodal staging system considers applying different systems according to the RLN.