Background: We evaluated the impact of the number of metastatic lymph nodes and the metastatic lymph nodes ratio (the ratio between metastatic lymph nodes and total dissected lymph nodes, MLNR) in patients with gastric adenocarcinoma following curative gastrectomy and also analyzed the relationship between the number of removed lymph nodes and prognosis in node-negative gastric cancer.
Methods: From January 2005 to December 2010, 1 390 patients who were diagnosed with gastric adenocarcinoma and underwent curative gastrectomy were included. In particular, lymph node metastasis was not present in 515 patients. The number of metastatic lymph nodes and the metastatic lymph nodes ratio were selected for univariate and multivariate analyses to evaluate their influences on the disease outcome. The survival curve was presented according to the number of removed lymph nodes in node-negative gastric cancer using Kaplan-Meier plots.
Results: The overall 5-year survival rate was 54% in this group. Univariate analysis revealed that age category, macroscopic appearance, histological grade, tumor size, depth of primary tumor invasion, number of metastatic lymph nodes, metastatic lymph nodes ratio, tumor, nodes, metastasis-classification (TNM) stage and status of lymphovascular, and vessel invasion have significant impact on survival. The number of metastatic lymph nodes and the metastatic lymph nodes ratio both have significant impact on survival (P < 0.001). However, in multivariate analyses, only the metastatic lymph nodes ratio was identified to be an independent prognostic factor (P < 0.001). The number of removed lymph nodes in node-negative was a strong prognostic factor of survival, the more lymph nodes dissected, the better the survival.
Conclusions: The metastatic lymph nodes ratio has more significant prognostic value for survival in patients with gastric cancer following curative gastrectomy than the number of metastatic lymph nodes. The number of removed lymph nodes might be an important prognostic factor for gastric cancer without lymph node metastasis.