Determining of metastatic lymph node ratio in patients who underwent D2 dissection for gastric cancer

The purpose of this study was to determine outcome of the ratio of metastatic lymph nodes to the total number of dissected lymph nodes (MLR) in patients with gastric cancer. We retrospectively analyzed 111 patients who underwent D₂ lymph node dissection. The prognostic factors including UICC/AJCC TNM classification and MLR were evaluated by univariate and multivariate analysis. The MLR was significantly higher in patients with a larger tumor, lymphatic vessel invasion, blood vessel invasion and perineural invasion, and advanced stage. Moreover, the MLR was significantly associated with the depth of invasion and the number of lymph node metastasis. The univariate analysis revealed for overall survival (OS) that stage of disease, lymphatic vessel invasion, blood vessel invasion, perineural invasion, lymph node metastasis (UICC/AJCC pN stage) and MLR were relevant prognostic indicators. Furthermore, both UICC/AJCC pN stage and MLR were detected as prognostic factor by multivariate analysis, as was perineural invasion. Our results indicated that MLR and UICC/AJCC pN staging system were important prognostic factors for OS of patients with D₂ lymph node dissection in gastric cancer in a multivariate analysis. MLR may be useful for evaluating the status of lymph node metastasis in gastric cancer.