Predictive factors of lymph node metastasis in patients with undifferentiated early gastric cancers

Background: For intramucosal differentiated early gastric cancer that has little risk of lymph node metastasis, local treatment such as endoscopic mucosal resection has been generally accepted as an adequate treatment. We studied clinicopathological characteristics of undifferentiated early gastric cancer at our institution to identify the predictive factors for lymph node metastasis and qualify lesions that should be referred for gastrectomy and not endoscopic mucosal resection. Methods: We retrospectively analyzed the clinicopathological features (patient age and gender, tumor size, location, macroscopic type and histological type, presence of ulceration, depth of tumor invasion, and lymphatic-vascular involvement) in 332 patients with undifferentiated early gastric cancer who underwent gastrectomy with regional lymph node dissection. Results: Lymph node metastasis was observed in 45 patients (14%). Univariate analysis revealed that depth of tumor invasion (submucosa), tumor size ( > 30 mm), and lymphatic-vascular involvement (positive) were associated with lymph node metastasis. Only lymphatic-vascular involvement (positive) was found to have a significant association (odds ratio, 7.4; 95% confidence interval, 2.9-19.0) by multivariate analysis. Conclusions: Lymphatic-vascular involvement was the only independent predictive risk factor for lymph node metastasis. This pathologic factor was not useful for identifying patients at high risk of lymph node metastasis who should be offered gastrectomy rather than endoscopic mucosal resection.