RESUMEN
PURPOSE: Whereas lymph node metastasis in gastric cancer is an important prognostic factor, the prognostic relevance of occult tumor cells in lymph nodes has not yet been elucidated. The aims of this study were to assess the incidence of micrometastases of lymph nodes in patients with submucosally invaded gastric cancer and to investigate whether micrometastases of lymph nodes have prognostic significance. METHODS: In order to evaluate the incidence of lymph node micrometastases in patients with submucosal gastric cancer, 1423 lymph nodes taken from 55 patients were assessed by immunohistochemical technique using a monoclonal anti-human cytokeratin-8. Clinicopathologic parameters and prognoses were compared between patients with and without micrometastases. RESULTS: The incidence of nodal involvement by tumor cells in 55 patients with submucosal gastric cancer increased from 20.0% (11 patients) by hematoxylin-eosin (H-E) staining to 30.8% (17 patients) by immunohistochemical staining. Nodal positivity in this study increased from 0.8% (12/1423 nodes) by H-E staining to 3.2% (45/1423 nodes) by immunohistochemical staining (p=0.003). The presence of cytokeratin positivity was not related to various clinicopathologic factors. As estimated by the Kaplan-Meier lifetable methods, there was no significant difference in the five-year survival rate between the micrometastases negative and positive groups (94.8% and 94.1%, respectively). CONCLUSION: The presence of nodal micrometastases detected by immunohistochemical technique is an interesting phenomenon, however clinically it seems to be of only weak prognostic value in submucosal gastric cancer.