Lymph node metastasis as a significant prognostic factor in early gastric cancer: Analysis of 1,136 early gastric cancers

Background: Gastric cancer is the most frquent cancer and the leading cause of death from cancer in Korea. Early gastric cancer has been defined as a gastric carcinoma confined to mucosa or submucosa, regardless of lymph node status, and has an excellent prognosis with a >90% 5-year survival rate. From 1974 to 1992, we encountered 7,606 cases of gastric cancer and performed 6,928 gastric resections. Among them, 1,136 cases were early gastric cancer (14.9% of all gastric cancer cases and 16.4% of resected gastric cancer cases). Methods: A retrospective analysis of 1,136 cases of early gastric cancer was performed to evaluate the prognostic significance of clinicopathologic features (sex, age, tumor location, gross type, histologic type, depth of invasion, status of lymph node metastasis, resection type). Lymph node metastasis was classified into three groups: N(n=0) for no lymph node metastasis; N(n=1–3) for one to three lymph node metastases; and N(n>3) for more than three lymph node metastases. All patients received radical total or subtotal gastrectomy with lymph node dissection. Results: In univariate and multivariate analysis of these nine factors, the only statistically significant prognostic factor was regional lymph node metastasis (p<0.001). The others had no statistically significant association with prognosis. Lymph node metastasis was present in 178 cases (15.7%). The factors associated with the lymph node metastasis were depth of invasion and gross type protruding type (e.g., types I, IIa)]. One hundred twenty-five of these patients had one to three lymph node metastases, and 53 cases had more than three lymph node metastases. The difference in 5-year survival rates among these groups was statistically significant: 94.5% for N(n=0), 88.3% for N(n=1–3), and 77.3% for N(n>3). Conclusion: We propose that for early gastric cancer, lymph node dissection is necessary in addition to gastric resection, at least in patients with a high risk of lymph node metastasis.