Prognostic assessment of different metastatic lymph node staging methods for gastric cancer after D2 resection

摘要

AIM: To compare the prognostic assessment of lymph node ratio and absolute number based staging system for gastric cancer after D2 resection.METHODS: The clinical, pathologic, and long-term follow-up data of 427 patients with gastric cancer that underwent D2 curative gastrectomy were retrospectively analyzed. The relationships between the metastatic lymph node ratio (MLR), log odds of positive lymph nodes (LODDS), and positive lymph nodes (pN) staging methods and the long-term prognoses of the patients were compared. In addition, the survival curves, accuracy, and homogeneity were compared with stratification to evaluate the prognostic assessment of the 3 methods when the number of tested lymph nodes was insufficient (< 10 and 10-15).RESULTS: MLR [hazard ratio (HR) = 1.401, P = 0.012], LODDS (HR = 1.012, P = 0.034), and pN (HR = 1.376, P = 0.005) were independent risk factors for gastric cancer patients. The receiver operating characteristic (ROC) curves showed that the prognostic accuracy of the 3 methods was comparable (P > 0.05). Spearman correlation analysis confirmed that MLR, LODDS, and pN were all positively correlated with the total number of tested lymph nodes. When the number of tested lymph node was < 10, the value of survival curves staged by MLR and LODDS was superior to those of pN staging. However, the difference in survival curves between adjacent stages was not significant. In addition, the survival rate of stage 4 patients using the MLR and LODDS staging methods was 26.7% and 27.3% with < 10 lymph node, respectively which were significantly higher than the survival rate of patients with > 15 tested lymph nodes (< 4%). The ROC curve showed that the accuracy of the prognostic assessment of MLR, LODDS, and pN staging methods was comparable (P > 0.05), and the area under the ROC curve of all 3 methods were increased progressively with the enhanced levels of examined lymph nodes. In addition, the homogeneity of the 3 methods in patients with ≤ 15 tested lymph nodes also showed no significant difference.CONCLUSION: Neither MLR or LODDS could reduce the staging bias. A sufficient number of tested lymph nodes is key to ensure an accurate prognosis for patients underwent D2 radical gastrectomy.