Immunohistochemically detected micrometastasis in lymph nodes from superficial esophageal squamous cell carcinoma

BACKGROUND AND OBJECTIVES: This study was conducted to determine the incidence and clarify the patterns of nodal micrometastasis, to elucidate the histopathologic parameters of tumor extension correlating with micrometastasis, and to evaluate whether nodal micrometastasis has clinical significance in patients with superficial esophageal cancer. METHODS: Lymph nodes resected from 78 patients with superficial esophageal squamous cell carcinoma were examined immunohistochemically using the monoclonal antibody cocktail AE1/AE3 to define histologically undetectable micrometastasis. Clinical records and pathologic features of all cases were reviewed. RESULTS: Of the 78 patients, 34 had neither micro- nor overt disease in the lymph nodes, 12 had nodal micrometastasis only, and 32 had histologically overt metastasis. Nodal micrometastasis was found in carcinomas reaching the muscularis mucosae or deeper tissues of the esophagus. Multivariate analysis showed that intraesophageal multicentric cancer and venous invasion had significant correlation with nodal micrometastasis (P = 0.005 and 0.017, respectively). However, no clinical impact of nodal micrometastasis could be detected regarding patient outcome. CONCLUSIONS: Nodal micrometastasis is not rare in patients with superficial esophageal cancer, but it does not appear to have clinical significance in these patients. Nodal micrometastasis correlates with intraesophageal multicentric cancer and venous invasion.