Lymph Node Mapping in Gallbladder Cancers: Analysis to Assess the Impact of Location and Number of Lymph Nodal Stations.

Abstract

Background and objectives: The current staging for gallbladder cancer (GBC) considers only the number of metastatic lymph nodes without addressing their location. This study evaluates the prognostic impact of lymph node mapping (both number and location) in node positive GBC.

Methods: Prospectively maintained operative database of operated GBC patients from April 2010 to March 2022 with positive lymph nodes was analyzed. Nodal burden was assessed by the number and meticulous mapping of the involved nodal stations. Outcomes were evaluated using Cox regression analysis. A new nodal staging system was formulated and compared with the current American Joint Committee for Cancer Care (AJCC) staging.

Results: 222 node positive patients were included. Multivariate analysis showed that multi-station involvement was significantly associated with poor disease-free survival (DFS) (Hazard ratio [HR]: 0.522 [95% CI: 0.354-0.770]; p = 0.001). The 5-year DFS of 42.9%, 35.5%, 17% and 13% (p = 0.023) respectively was observed for positive cystic node (N1a), single positive non-cystic node (N1b), 2 and 3 positive nodes (N2a and N2b) with multi-station involvement. The Concordance index for the new staging system was 0.588 reflecting a 6.9% absolute improvement in the prediction capability.

Conclusions: Station-based nodal assessment predicted for survival in our node positive cohort. Pathological assessment of involved stations, in addition to the number of involved nodes, could potentially provide superior prognostic information. However, this needs to be evaluated prospectively in larger cohorts.