Lymph node metastases in gastric cancer: significance of positive number.

To investigate the significance of the number of node metastases in gastric cancer and its relationship to traditional anatomical classification, 305 patients who underwent a radical gastrectomy and extended lymphadenectomy (R3/4) with curative intent were reviewed. Lymph node metastases was found in 191 (62.6%) patients. The incidence of lymph node metastases was closely related to the depth of cancer invasion as well as the extent of lymph node group involvement. The frequency of metastases in different lymph node locations was related to the location of the primary tumor. The 3-year survival rates for patients with node involvement and without were 42.1 and 92.3%, respectively. In node number analysis, the distribution of the N1 group and the N4 group involvement was rather characteristic and could be predicted from a node number < 4 or > 12. The predictability of N2 and N3 involvement from node numbers 4-8 and 9-12 was less satisfactory. On the whole, patients with a metastatic node number < 4 could be considered to be N1 and had a relative good prognosis. Patients with node number 4-10 could be considered as N2 and > 10 as an incurable disease with distant metastases. Both had a poor prognosis. The data suggest that lymph node number represents the biologic behavior of cancer instead of the anatomic consideration of conventional N stage. The number of metastatic lymph node number is a good prognostic indicator with similar predicting power as the conventional node stage.