Micrometastasis in lymph nodes of mucosal gastric cancer

BACKGROUND: Endoscopic mucosal resection is frequently used in the treatment of mucosal gastric cancer. Micrometastasis in the lymph nodes of mucosal gastric cancer remains unclear.METHODS: We examined 2526 lymph nodes from 84 patients with mucosal gastric cancer. Two consecutive sections were prepared, for simultaneous staining with hematoxylin and eosin and immunostaining with CAM 5.2 monoclonal antibody against cytokeratin (CK), respectively. A clinicopathological comparison was made between patients with and without lymph node involvement.RESULTS: Lymph node involvement was detected in 45 of 2526 (1.8%) lymph nodes. The incidence of nodal involvement was significantly increased, from 1.2% (1/84 patients) with hematoxylin and eosin staining, to 19% (16/84 patients) with CK immunostaining. Although no significant difference was found, micrometastasis to lymph nodes was more frequently detected in tumors larger than 1.0 cm (15/72 patients, 21%) than in those less than or equal to 1.0 cm (1/12 patients; 8%, P = 0.307). However, discrete CK-positive cancer cells or clusters of CK-positive cancer cells were detected only in tumors larger than 2 cm.CONCLUSION: Because mucosal gastric cancer of more than 1.0 cm in superficial diameter may indicate a risk of micrometastasis to lymph nodes, endoscopic mucosal resection is not recommended for these patients.