Background: Gastric carcinoma invading the submucosa is often accompanied by lymph node metastasis. However, the relation between the depth of submucosal invasion and the status of metastasis has not been investigated. The objective of this study was to clarify the relation between lymph node status and the histologic features of gastric carcinoma invading the submucosa.
Methods: The histopathology of 118 patients who underwent gastrectomy and lymph node dissection for gastric carcinoma invading the submucosa was examined. These pT1 tumors with invasion of the submucosa were confirmed by histologic examination of the resected specimens. Tumor size, depth of submucosal invasion, histologic type, and macroscopic type were investigated in association with presence or absence of and anatomic level of lymph node metastasis.
Results: Among the 118 patients, 16 (14%) had lymph node metastasis, and the status of metastasis significantly correlated with tumor size and depth of submucosal invasion. The frequency of metastasis to perigastric lymph nodes and extragastric lymph nodes was 0% and 0% for < or =1-cm tumors, 5% and 1% for 1- to 4-cm tumors, and 46% and 15% for >4-cm tumors, respectively. There was no lymph from a node metastasis in tumors with less than 300 microm of submucosal invasion. The frequency of lymph node metastasis for tumors with 300-1000 microm and >1000 microm of submucosal invasion were 19% and 14%, respectively.
Conclusions: Tumor size and depth of submucosal invasion serve as simple and useful indicators of lymph node metastasis in early stage gastric carcinoma. Optimal lymph node dissection levels are as follows: 1) local resection (D0) for lesions < or =1 cm, 2) limited lymph node dissection (D1) for 1- to 4-cm lesions, and 3) radical lymph node dissection (D2) for lesions >4 cm. When submucosal invasion of a locally resected tumor is more than 300 microm, additional gastrectomy and lymph node dissection are necessary.