Prognostic Impact of Lymph Node Excision in T1 and T2 Gallbladder Cancer: a Population-Based and Propensity Score-Matched SEER Analysis.

The aim of this study was to assess the effect of lymphadenectomy on survival in T1/T2 gallbladder cancer (GBC). In this retrospective cohort study, patients undergoing surgery for T1/T2 GBC from 2004 to 2014 were identified in the Surveillance, Epidemiology, and End Results database. The effect of lymph node excision (LNE) on survival was assessed using Cox regression and propensity score methods. A total of 2112 patients were identified: 11.4% had T1a, 18.5% T1b, and 70.1% had T2 tumors. Mean follow-up was 31.3 months. In 48.8% of patients, LNE was performed with a mean of 3.6 ± 4.3 nodes retrieved. Cancer-specific 5-year survival for T1 and T2 stages combined was 49.6% (95% confidence interval (CI), 45.9-53.6%) without LNE compared to 56.2% (95% CI, 52.4-60.4%) if LNE was performed (hazard ratio (HR), 0.75; 95%CI, 0.64-0.86, P < 0.001). Propensity score analyses for both stages combined confirmed this survival benefit with an HR of 0.67 (95% CI, 0.55-0.80) for the LNE group (P < 0.001). Stratified for tumor stages, LNE had no significant effect on cancer-specific survival in T1a (HR, 1.80 (95% CI, 0.76-4.26), P = 0.185) or T1b tumors (HR, 0.95 (95% CI, 0.57-1.58), P = 0.844), whereas it persistently revealed an advantage for patients with T2 tumors (HR 0.68 (95% CI, 0.55-0.83, P < 0.001). No correlation between the number of retrieved lymph nodes and the N+ rate was found (P = 0.134). LNE is associated with improved survival in T2 GBC. No significant survival benefit was observed in T1a and T1b tumors. The retrieval of even a few lymph nodes reliably predicts the nodal status, which might assist in patient selection for re-resection in T1 GBC.