Implications of inadequate lymph node staging in resectable gastric cancer: a contemporary analysis using the National Cancer Data Base.

ABSTRACT

BACKGROUND: National guidelines recommend examination of ≥ 15 lymph nodes for adequate staging of resectable gastric adenocarcinoma (GA). The relevance of these guidelines, which were established before the increasing use of multimodality therapy, and the impact of inadequate lymph node staging (LNS) in a contemporary cohort have not been extensively explored. METHODS: Stage I-III GA patients who underwent gastrectomy from 1998 to 2011 were identified using the National Cancer Data Base. Trends in LNS adequacy, predictors of inadequate LNS (< 15 LN examined) and the relationship between LNS and overall survival (OS) were analyzed. RESULTS: In 22,409 patients, compliance with LNS guidelines was poor (inadequate LNS in 61.2% of cases, median LN harvested in 11.0%). Subtotal/partial gastrectomy was the strongest predictor of inadequate LNS (OR = 2.01, P < .001). Survival analyses included 9139 patients with minimum 5 years follow-up; median, 1-year, and 5-year survival was 35.6 months, 75.5%, and 39.7%, respectively. LN positivity (HR = 1.90) and age > 76 years (HR = 1.73) were the strongest predictors of worse OS (both P < .001). Inadequate LNS was independently associated with worse OS (HR = 1.33, P < .001). Median OS after inadequate compared to adequate LNS was significantly worse (33.3 months versus 42.0 months, P < .001), regardless of AJCC clinical stage subgroup or tumor T classification (both P < .001). CONCLUSIONS: Adequate LNS is achieved in a minority of patients. Inadequate LNS was independently associated with worse OS. Examination of ≥ 15 LN is a reproducible prognosticator of gastric cancer outcomes in the United States and should continue to serve as a benchmark for quality of care.