The Comparison between 6th and 7th UICC/AJCC N Stage for Prognostic Significance in Gastric Cancer

PURPOSE: The 7th edition UICC/AJCC TNM classification for gastric cancer has several changes from the previous edition. Especially, the classification of the number of lymph node metastases (LNM) is reorganized. According to the new TNM system, N stage was categorized to N0 (no LNM), N1 (1~2 LNM), N2 (3~6 LNM), N3 (7 or more LNM). The aim of our study was to compare the prognostic significance of the new (7th) UICC/AJCC N stage with the old (6th). METHODS: From 2000 to 2005 a total of 425 patients who underwent curative resections with D2 and with 15 or more lymph nodes retrieved were studied retrospectively. RESULTS: According to the 7th UICC/AJCC N stage, the 5-year cumulative survival rates (5YSR) of N0, N1, N2, N3 were 96.0%, 79.2%, 58.5% and 24.3%, respectively (P<0.001). Using univariate analysis, the N stage of 7th and 6th UICC/AJCC TNM classification, 7th UICC/AJCC T stage, differentiation of tumor, type of gastrectomy (subtotal and total gastrectomy), size of primary tumor (< or =5, 5<< or =10, 10<) were associated with 5YSR. However, Cox regression multivariate analysis showed the 7th UICC/AJCC N stage to bean independent factor for predicting the 5YSR instead of the 6th UICC/AJCC N stage (P<0.001, hazard ratio (HR) 1.859, 95% confidence interval (CI) 1.576~2.194), including depth of tumor invasion (P<0.001, HR 1.673, 95% CI 1.351~2.073). CONCLUSION: The new (7th) UICC/AJCC N stage is a more reliable prognostic factor of gastric cancer than the old (6th) N stage.

Does the New UICC/AJCC TNM Staging System (7th Edition) Improve Assessing Prognosis in Gastric Cancer Compared to the Old System (6th Edition)?

PURPOSE: We evaluated the efficacy and prognostic predictability of the 7th UICC TNM classification compared to 6th UICC TNM classification in patients with gastric cancer. MATERIALS AND METHODS: Between June 1992 and December 2006, 1,633 patients with gastric cancer who had undergone gastric surgery and who had been analyzed by the 6th UICC method were analyzed using the new 7th UICC system. RESULTS: Significant differences in 5-year survival rates were observed for 7th UICC N0, N1, N2, N3a, and N3b compared to 6th UICC. There were no significant differences in 5-year survival rates between T2 and T3. Distinct survival differences were present between stage III (IIIa, IIIb, and IIIc) and stage IV in 7th UICC. Significant differences in 5-year survival rates were not expected for Ia versus Ib, Ib versus IIa, and IIb versus IIIa. The survival rates for the same stages were not homogeneously differentiated by 7th UICC except for stage IV. CONCLUSION: The 7th UICC classification system is not better able to predict patient survival compared to 6th UICC in patients with gastric cancer, but is better for accurate prognosis of patients with stage IV gastric cancer.