A comparison of the operative outcomes of D1 and D2 gastrectomy performed at a single Western center with multiple surgeons: a retrospective analysis with propensity score matching

BACKGROUND: There has been worldwide debate on lymphadenectomy for gastric cancer, with increasing consensus on performing an extended (D2) resection. There is a paucity of data in Australia. Our aim is to compare overall outcomes between a D1 and D2 lymphadenectomy for gastric cancer in a single specialist unit. METHODS: We performed a retrospective analysis on patients who underwent a curative primary gastric resection for gastric adenocarcinoma between January 1996 and April 2016, primary outcomes included overall survival (OS) and disease-free survival (DFS). Propensity score matching (PSM) analysis was used to balance covariates between D1/D1+ and D2 groups. Kaplan-Meier survival curves of D1/D1+ versus D2 were constructed and evaluated using the log-rank test with subgroup analyses for pathological node (pN) status. Multiple Cox proportional hazards model was used to determine predictors of overall survival. RESULTS: Two hundred four patients underwent a gastrectomy, 54 had D1/D1+, and 150 had a D2 lymphadenectomy. After PSM, there were 39 patients in each group, the 10-year OS for D1/D1+ was 52.1 and 76.2% for D2 (p = 0.008), and 10-year DFS was 35% for D1 and 58.1% for D2 (p = 0.058). Subgroup analysis showed that node-negative (N0) patients had improved 5-year OS for D2 (90.9%), compared to D1/D1+ (76.4%) (p = 0.028). There was no difference in operative mortality between the groups (D1 vs D2: 2 vs 0%, p = 0.314), nor in post-operative complications (p = 0.227). Multiple Cox analysis showed advanced tumor stage (stages III and IV), and lymphadenectomy type (D1) and the presence of postoperative complications were independent predictors of poor overall survival. CONCLUSIONS: D2 lymphadenectomy with spleen and pancreas preservation can be performed safely on patients with gastric adenocarcinoma. Significant improvement in overall survival is observed in patients with N0 disease who underwent D2 lymphadenectomy without increasing operative morbidity or mortality. This paper supports the notion of a global consensus for a D2 lymphadenectomy, particularly in the Western context.