Evaluation of the necessity for gastrectomy with lymph node dissection for patients with submucosal invasive gastric cancer

Background: When cancer cells are found in the submucosal layer of an endoscopically resected specimen, patients are recommended to undergo gastrectomy with lymph node dissection. If it were possible to identify those patients in whom the risk of lymph node metastasis was negligible, it might be possible to avoid surgery. Methods: Among those who underwent gastrectomy for gastric cancer from 1980 to 1999, 1091 patients with a cancer invading the submucosa were studied. Clinicopathological factors (sex, age, tumour location, macroscopic type, size, ulceration, histological type, lymphatic-vascular involvement and degree of submucosal penetration) were investigated for their possible association with lymph node metastasis. Results: Lymph node metastases were found in 222 patients (20.3 per cent). Univariate analysis showed that larger tumour size (more than 30 mm), undifferentiated histological type, lymphatic-vascular involvement and massive submucosal penetration had a significant association with lymph node metastasis. Tumour size, histological type and lymphatic-vascular involvement were independent risk factors for lymph node metastasis. By combining these three factors with submucosal penetration of less than 500 mum, 117 patients could be selected as having a minimal risk of lymph node metastasis (95 per cent confidence interval 0-3.1 per cent). Conclusion: Lymphadenectomy may not be necessary for patients with gastric cancer invading the submucosa who fulfil the above conditions.