Effect of lymphadenectomy in curative gallbladder cancer treatment: a systematic review and meta-analysis.

Only a small fraction of resectable gallbladder cancer (GBC) patients receive a thorough lymphadenectomy. The aim of this systematic review and meta-analysis was to investigate the effect of lymphadenectomy on survival in GBC surgery. On May 19, 2019, MEDLINE, EMBASE, and the Cochrane Library were searched for English or German articles published since 2002. Studies assessing the effect of lymphadenectomy on survival in GBC surgery were included. Fixed effect and random effects models were used to summarise the hazard ratio (HR). Of the 530 identified articles, 18 observational studies (27,570 patients, 10 population-based, 8 cohort studies) were reviewed. In the meta-analysis, lymphadenectomy did not show a significant benefit for T1a tumours (n = 495; HR, 1.37; 95%CI, 0.65-2.86; P = 0.41). Lymphadenectomy showed a significant survival benefit in T1b (n = 1618; HR, 0.69; 95%CI, 0.50-0.94; P = 0.02) and T2 (n = 6204; HR, 0.68; 95%CI, 0.56-0.83; P < 0.01) tumours. Lymphadenectomy improved survival in the 2 studies assessing T3 tumours (n = 1961). A conclusive analysis was not possible for T4 tumours due to a low case load. Among patients undergoing lymphadenectomy, improved survival was observed in patients with a higher number of resected lymph nodes (HR, 0.57; 95%CI, 0.45-0.71; P < 0.01). Regional lymphadenectomy improves survival in T1b to T3 GBC. A minimum of 6 retrieved lymph nodes are necessary for adequate staging, indicating a thorough lymphadenectomy. Patients with T1a tumours should be evaluated for lymphadenectomy, especially if lymph node metastases are suspected.