Nodal Staging by Number of Metastatic Lymph Node and Comparison with Nodal Staging of 5th UICC TNM Classification in Gastric Cancer

PURPOSE: The nodal staging of the 5th edition of the Union Internationale Contra la Cancer (UICC) TNM classification in 1997 was changed based on the number of metastatic lymph nodes. We attempted to classify nodal status according to the number of involved lymph nodes and compare with the nodal staging of the 5th UICC TNM classification in order to evaluate the rationality of the new nodal staging system. METHODS: The authors retrospectively analyzed 427 patients with gastric cancer who underwent curative resection from 1993 to 1996 at the Department of Surgery, Korea University College of Medicine. Cumulative survival rates were calculated by the Kaplan-Meier method. The difference between each nodal status was evaluated by the log rank test and the generalized Wilcoxon test. RESULTS: There were statistical differences between 0 and 1 lymph node involved, between 7 and 8, and between 15 and 16. We classified the nodal status into 4 groups according to the number of involved lymph nodes based on the following: group 1 with no lymph node involved, group 2 with 1~7, group 3 with 8~15 and group 4 with more than 15. There was a significant survival difference among the 4 groups with no survival difference between the number of positive lymph nodes in each group. We compare our results with the nodal staging of the UICC TNM classification and found that there were differences between group 2 (1~7 positive lymph nodes) and pN1 of TNM (1~6 positive lymph nodes) and between group 3 (8~15) and pN2 (7~15). CONCLUSION: We were able to classify nodal status into 4 groups according to the number of involved lymph nodes. There was little difference compared with the new nodal staging of the 5th UICC TNM classification, which suggested that the nodal classification of the UICC TNM classification based on the number of metastatic lymph nodes is acceptable. Further analysis of a larger sample size may be necessary.

Influence of Nodal Yields on Staging of Gastric Cancer and on Survival

PURPOSE: In the fifth edition of International Union Against Cancer (UICC) TNM, nodal staging for gastric cancer is based on the number of metastatic lymph nodes. Variability in the extent of lymphadenectomy and lymph node retrieval can affect the number of metastatic lymph nodes. In this study, the authors attempted to evaluate the influence of nodal yields on the staging of gastric cancer and survival rates. METHODS: A retrospective study was performed in 4354 consecutive patients with gastric cancer, who had undergone curative resection (R0) with nodal yields of 15 or more from 1986 to 1995. Patients were classified into three groups according to the number of nodes examined: patients with nodal yields of 15 or more but less than 30 for group A, 30-39 for group B, and 40 or more for group C. The number of metastatic lymph nodes and the survival rates for each pTNM stage were analyzed for each group. RESULTS: The number of metastatic lymph nodes significantly increased with nodal yields. Greater nodal yields resulted in a higher survival rates with a statistically significant difference between patients with nodal yields of 30 or more, and those with less than 30 in stage IB (p<0.05) and IIIB (p<0.01). CONCLUSION: Our results suggest two possibilities of stage migration and survival benefit according to the difference of nodal yields. Therefore, for minimizing stage migration and maximizing the benefit of survival, at least 30 or more lymphnodes should be resected and examined in gastric cancer surgery.