Metastatic lymph node ratio: a new staging system for gastric cancer.

Background: This study was designed to analyze the prognostic significance of the staging system based on the ratio of metastatic lymph nodes (TRM) compared with the TNM staging system in patients with gastric cancer.

Methods: We reviewed the data of 219 patients who underwent gastrectomy for node-positive M0 cancer. Node Ratio (NR) categories (NR1: 1-15%; NR2: 16-40%; NR3: >40%) were determined by the best cutoff approach at log-rank test. After confirming the prognostic validity of NR in a collinearity-free Cox regression analysis, among different combinations of pT and NR categories we selected five prognostically homogeneous TRM classes. To compare the prognostic power of the TRM vs. TNM systems, we plotted TRM and TNM classes against the mortality estimates.

Results: Both of the TRM and TNM classifications significantly stratified patients outcomes (p < 0.0001), but the TRM system identified prognostic subgroups more homogeneous than the TNM system.

Conclusions: The TRM staging system is a simple and reliable tool to stratify patients with gastric cancer and has a higher prognostic power than the current system.