Lymph node ratio is a better prognosticator than lymph node status for gastric cancer: A retrospective study of 138 cases

To study the clinical significance of lymph node ratio (LNR) in gastric cancer (GC), this study analyzed 613 patients with GC who underwent surgical resection. Of 613 patients with GC, 138 patients who had >15 lymph nodes (LNs) resected and radical resection were enrolled into the final study. All major clinicopathological data were entered into a central database. LNR was defined as the ratio of the number of metastatic LNs to the number of removed LNs. In order to determine the best cut-off points for LNR, the log-rank test and X-tile were used. LNR was then substituted for lymph node status (pN) in the 7th American Joint Committee on Cancer tumor-node-metastases (TNM) staging system and this was defined as the tumor-node ratio-metastases (TRM) staging system. Pearson's correlation coefficient (r) was used to study the correlations among the number of removed LNs, pN and LNR. The Kaplan-Meier survival curve was used to study the survival status, and the log-rank test and Cox proportional hazards model were used to identify the independent factors for survival. Receiver operating characteristic curve analysis was used to determine the predictive value of the parameters. By the time of last follow-up (median follow-up period, 38.3 months; range, 9.9–97.7 months), the median overall survival (OS) was 23.9 months [95% confidence interval (CI), 18.8–29.0 months]. The 1-, 2-, 3- and 5-year survival rates were 76.8, 57.2, 50.0 and 46.4%, respectively. The cut-off points were 0, 0.5 and 0.8 (R0, LNR=0; R1, LNR ≤0.5; R2, 0.5> LNR ≤0.8; and R3, LNR >0.8). Univariate and multivariate analyses revealed that both LNR and pN were independent prognostic factors for GC. LNR could better differentiate OS in patients than LN. In addition, the TRM staging system was better at predicting the clinical outcomes than the TNM staging system, and LNR was better than pN. In conclusion, LNR was a better prognosticator than pN for GC.