BACKGROUBD: In the new UICC TNM classification for gastric cancer, the anatomical extent of nodal metastasis has been replaced by the numerical rate of metastatic nodes. The aim of this investigation was to evaluate the prognostic value of the new staging system compared to the old one.
METHODS: Clinicopathological parameters of 300 patients who underwent potentially curative resections with D2 or D3 lymph node dissection for gastric adenocarcinoma were reviewed. The inclusion criteria included: 15 or more lymph nodes dissected and a minimum follow-up of 60 months. The statistical methods used to analyse prognostic value were: Kaplan-Meier survival curves; the log-rank test for univariate analysis; and Cox's model for multivariate analysis.
RESULTS: 63.8% were men, with a mean age of 61.1 ± 12.8 years. Total gastrectomy was performed in 39.4% and subtotal in 61.6%. Intestinal type tumors were diagnosed in 59.1%. Early carcinoma was present in 12.8% of the cases. The mean number of dissected lymph nodes per case was 29.5 ± 16.8 (range= 16 to 84), and the mean number of metastatic nodes was 3.8 ± 7.3 (range= 0 to 49). The median follow-up period was 54 months. Among patients classified as pN1 by the old staging system, 11.1% were up-staged as pN2 according to the new staging. In pN2, same stage was observed in 31.1%, down-staged in 39.3% and up-staged in 29.6% patients. There was a significant correlation between the two staging systems, p=0.00001. The overall survival rate of 300 patients was 46%. The mean overall survival rates for patients classified as pN1 and pN2 according to the anatomic staging system were 60 months and 41 months, respectively, and the rates for patients according to the new staging group were 51 months in pN1, 43 months in pN2 and 19 months in pN3. In multivariate analysis both staging systems were significant prognostic factors.
CONCLUSIONS: 1. The new staging system is simple and reliable as a prognostic determinant in gastric cancer; 2. The evaluation of number of positive nodes could permit a stratification of the old N2, that revealed a group of patients with worst outcome.