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

Background: When cancer cells are found in the submucosal layer of an endos copically resected specimen, patients are recommended to undergo gastrectom y with lymph node dissection. If it were possible to identify those patient s in whom the risk of lymph node metastasis was negligible, it might be pos sible 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, s ize, ulceration, histological type, lymphatic-vascular involvement and degr ee of submucosal penetration) were investigated for their possible associat ion 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), undif ferentiated histological type, lymphatic-vascular involvement and massive s ubmucosal penetration had a significant association with lymph node metasta sis. Tumour size, histological type and lymphatic-vascular involvement were independent risk factors for lymph node metastasis. By combining these thr ee factors with submucosal penetration of less than 500 mum, 117 patients c ould 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.