Abstract
This study aimed to assess the prognostic value of the hypothetical tumor-N-ratio (rN)-metastasis (TrNM) staging system in adenocarcinoma of the esophagogastric junction (AEG). The clinical data of 387 AEG patients who received surgical resection were retrospectively reviewed. The optimal cut-off point of rN was calculated by the best cut-off approach using log-rank test. Kaplan-Meier plots and Cox regressions model were applied for univariate and multivariate survival analyses. A TrNM staging system based on rN was proposed. The discriminating ability of each staging was evaluated by using an adjusted hazard ratio (HR) and a -2log likelihood. The prediction accuracy of the model was assessed by using the area under the curve (AUC) and the Harrell's C-index. The number of examined lymph nodes (LNs) was correlated with metastatic LNs (r = 0.322, P < 0.001) but not with rN (r = 0.098, P > 0.05). The optimal cut-points of rN were calculated as 0, 0~0.3, 0.3~0.6, and 0.6~1.0. Univariate analysis revealed that pN and rN classifications significantly influenced patients' RFS and OS (P < 0.001). Multivariate analysis adjusted for significant factors revealed that rN was recognized as an independent risk factor. A larger HR, a smaller -2log likelihood and a larger prediction accuracy were obtained for rN and the modified TrNM staging system. Taken together, our study demonstrates that the proposed N-ratio-based TrNM staging system is more reliable than the TNM staging system in evaluating prognosis of AEG patients after curative resection.