The superiority of ratio-based lymph node staging in gastric carcinoma

The need for a precise lymph node staging without stage migration is of paramount importance when comparing and evaluating international treatment results. We reviewed 1019 patients who underwent R0 resection at Kansai Medical University between 1980 and 1997. The patients were classified according to the 1997 International Union Against Cancer (UICC)/American Joint Committee on Cancer (AJCC) pN classification or the N staging depending on the ratio between the number of excised and the number of involved lymph nodes (pN1, < or = 25%; pN2, < or = 50%; pN3, >50%). Among the 1997 UICC/AJCC pN subgroups, prognosis worsened with an increase in lymph node ratio. In contrast, the ratio-based classification showed more homogenous survival according to the number of involved lymph nodes. Multiple stepwise regression analysis showed that the ratio-based classification was the most significant prognostic factor, whereas the 1997 UICC/AJCC classification was not found to be an independent predictor of survival. In addition, the ratio-based classification showed a superiority to the 1997 UICC/AJCC classification with respect to stage migration. Ratio-based lymph node staging is simple and gives more precise information for prognosis with fewer problems related to stage migration than the 1997 UICC/AJCC staging system.