Optimal extent of lymphadenectomy in gastric adenocarcinoma: A seven-institution study of the U.S. Gastric Cancer Collaborative.

Abstract

115 Background: The optimal extent of lymphadenectomy in the treatment of gastric adenocarcinoma continues to be a subject of intense debate. We aimed to compare gastrectomy outcomes following limited (D1) or extended (D2) lymphadenectomy. Methods: Using the multi-institutional U.S. Gastric Cancer Collaborative database, we reviewed the morbidity, mortality, recurrence, and overall survival (OS) of 727 patients receiving D1 or D2 lymphadenectomies. Patients with stage IV disease, prior gastrectomy, and age 85 or greater were excluded. Multivariate analyses included variables with p values less than 0.1. Results: Between 2000 and 2014, 266 (36.6%) and 461 (63.4%) patients received a D1 and D2 lymphadenectomy, respectively. ASA class, mean number of comorbidities, grade, stage, and signet ring cell subtypes were similar between groups. Neoadjuvant and adjuvant chemotherapy was more common in the D2 group (p<0.001). The mean number of lymph nodes recovered was significantly higher in patients receiving a D2 lymphadenectomy (21.5 for D2 vs. 17.1 for D1, p<0.001). Median follow up was 1.3 years. While Clavien III/IV major morbidity was similar (15.0% for D1 vs. 14.5% for D2, p=0.85), mortality was worse for those receiving a D1 lymphadenectomy (4.9% vs. 1.3%, p=0.004). Recurrence rates for patients receiving D1 and D2 lymphadenectomies were 25.8% and 27.0%, respectively (p=0.74). D2 lymphadenectomy was associated with improved median OS in stage I (4.7 years for D1 vs. not reached for D2, p=0.003) stage II (3.6 years for D1 vs. 6.3 for D2, p=0.42), and stage III patients (1.3 years for D1 vs. 2.1 for D2, p=0.01). After adjusting for significant predictors of OS which included ASA, stage, grade, neoadjuvant chemotherapy, and adjuvant radiation, D2 lymphadenectomy remained a significant predictor of improved survival when compared with D1 lymphadenectomy (HR 1.5, 95% CI 1.1-2.0, p=0.008). Conclusions: D2 lymphadenectomy is associated with improved survival that is more prominent in early stages of disease. It can be performed safely without increased risk of morbidity and perioperative mortality and should be the preferred lymphadenectomy technique for the treatment of gastric adenocarcinoma.