Does a minimum number of 16 retrieved nodes affect survival in curatively resected gastric cancer?

Background According to the TNM classification, the analysis of 16 or more lymph nodes is required for the appropriate staging of gastric cancer. The aim of this study was to evaluate whether this number of resected lymph nodes also affects survival. Methods This was a multicenter retrospective study based on an analysis of 992 patients with gastric adenocarcinoma who underwent curative resection between January 1980 and December 2009. Patients were classified according to the number of resected lymph nodes (<16 and ≥16 lymph nodes), the anatomical extent of lymph node dissection (D2 vs. D1), and the staging criteria of the seventh edition of the UICC/AJCC TNM staging system. Survival estimates were determined by univariate and multivariate analyses. Results Based on the univariate and multivariate analyses, the resection of 16 or more lymph nodes was associated with significantly better survival [p = 0.002; hazard ratio (HR) (95% confidence interval [CI]): 0.519 (0.345-0.780)]. Patients with a lymph node count <16 had a significantly worse survival rate than patients with a lymph node count ≥16 in the pN0 (p = 0.001), pN1 (p = 0.007) and pN2 (p = 0.001) stages. In the majority of cases, ≥16 lymph nodes were retrieved when D2 dissection was performed. Conclusions In gastric cancer the retrieval of less than 16 lymph nodes may cause inaccurate staging and/or inadequate treatment, thus affecting survival rates. These patients should be considered a high-risk group for stage migration and worse survival compared with those who have a retrieval of more than 16 lymph nodes. © 2015 Elsevier Ltd. All rights reserved.