The tumor-log odds of positive lymph nodes-metastasis staging system, a promising new staging system for gastric cancer after D2 resection in China.

BACKGROUND: In this study, we established a hypothetical tumor-lodds-metastasis (TLM) and tumor-ratio-metastasis (TRM) staging system. Moreover, we compared them with the 7(th) edition of American Joint Committee on Cancer tumor-nodes-metastasis (AJCC TNM) staging system in gastric cancer patients after D2 resection. METHODS: A total of 1000 gastric carcinoma patients receiving treatment in our center were selected for the analysis. Finally, 730 patients who received D2 resection were retrospectively studied. Patients were staged using the TLM, TRM and the 7(th) edition AJCC TNM system. Survival analysis was performed with a Cox regression model. We used two parameters to compare the TNM, TRM and TLM staging system, the -2log likelihood and the hazard ratio. RESULTS: The cut points of lymph node ratio (LNR) were set as 0, 0-0.3, 0.3-0.6, 0.6-1.0. And for the log odds of positive lymph nodes (LODDS), the cut points were established as≤-0.5, -0.5-0, 0-0.5, >0.5. There were significant differences in survival among patients in different LODDS classifications for each pN or LNR groups. When stratified by the LODDS classifications, the prognosis was highly homologous between those in the according pN or LNR classifications. Multivariate analysis showed that TLM staging system was better than the TRM or TNM system for the prognostic evaluation. CONCLUSIONS: The TLM system was superior to the TRM or TNM system for prognostic assessment of gastric adenocarcinoma patients after D2 resection.