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The Union Internationale Contre le Cancer/Tumor, Node, Metastasis (UICC/TNM, 5th edition) Classification established the number of the lymph nodes with metastatic deposits as the determinant factor for nodal category (N category) in patients with gastric cancer. This may suggest that N category could be influenced by the degree to which specimens are pathologically examined and the extension of lymph node surgical dissection. To correct this problem, the Lymph node ratio (LNR), which is the number of positive nodes divided by total number harvested, has been proposed. This study aims to investigate whether the LNR is a better prognostic factor as compared with N category (5th edition) proposed by the UICC in patients with gastric cancer. A retrospective review of a prospectively collected database of 63 patients with gastric cancer who underwent curative D2 gastrectomy between 2003 and 2007 was performed to determine the effect of the LNR on disease-free survival (DFS) and overall survival (OS). Prognostic factors were identified by univariate and multivariate analyses. Survival curves were constructed using the Kaplan-Meier method. The LNR was divided into four categories using the hazard ratio (HR). LNR categories (LNR 0= 0%; LNR 1= 1%–9%; LNR 2= 10%–25%; LNR 3= >25%) were determined by the best cut-off approach. After a median follow-up of 25.1 months (range, 4–32 months), analyzing the survival time comparing the lymph node ratio categories against the N categories (5th edition) demonstrated that the ratio stands out as the best prognostic factor. The implementation of proposed LNR nodal categories led to the identification of groups of patients prognostically more homogeneous than those classified by the UICC proposed nodal categories. Overall survival data according to LNR proposed nodal categories showed a statistically significant decrease in overall survival and disease free survival with increasing scores, which was more statistically significant than that observed with UICC proposed nodal categories (N categories, 5th edition), the LNR also discriminates different prognostic categories among patients with N1 and N2 lymph node involvement. In conclusion, LNR is a simple and reproducible prognostic tool that can stratify patients with gastric cancer. LNR gave a more accurate prognostic information from nodal involvement than the current N category of the TNM (5th edition). These data may represent the rational for improving the prognostic power of current UICC TNM staging system and ultimately the selection of patients who may most benefit from adjuvant treatments. |
