Survival impact of compliance in extra-perigastric lymphadenectomy for gastric cancer: 20 years of real-world data from a single institution

Compliance in lymphadenectomy was first introduced as part of quality control in a Dutch clinical trial. Although a few studies have investigated compliance, no studies have evaluated the survival impact at individual lymph node stations.In total, 2,932 patients who underwent radical gastrectomy between 1996 and 2014 at the Korea University Guro Hospital in Seoul, South Korea were retrospectively reviewed. We compared survival outcomes among the compliance, noncompliance, and metastatic groups.The highest compliance among extra-perigastric stations was recorded for #8a (86.6%), followed by #7 (76.6%) and #9 (68.3%). Stations #11 and #12 showed low compliance rates of 28.9% and 31.0%, respectively. Compliance at #7, #8a, and #9 was related to better 5-year relapse-free survival rates (74.5%, 72.8%, and 71.3%, respectively) than noncompliance (61.9% [hazard ratio, 1.72; 95% confidence interval, 1.40-2.11], 61.0% [hazard ratio, 1.6; 95% confidence interval 1.26-2.04], 65.3% [hazard ratio, 1.25; 95% confidence interval 1.04-1.51], respectively). At #11 and #12, there were no significant differences in relapse-free survival between compliance (69.1% and 70.2%, respectively) and noncompliance (67.4% [hazard ratio, 0.85; 95% confidence interval 0.53-1.36], 65.1% [hazard ratio, 1.13; 95% confidence interval 0.71-1.81], respectively). In multivariable analysis, stations #7 and #8 alone showed an increased hazard ratio of relapse-free survival in the noncompliance group relative to the compliance group.We showed a survival benefit of compliance during lymphadenectomy for gastric cancer. Although further prospective trials to validate our results are warranted, compliance could be adopted in real-world practice to achieve better survival among patients with gastric cancer.