Evaluation of an Indicator for Lymph Node Metastasis of Esophageal Squamous Cell Carcinoma Invading the Submucosal Layer

Lymph node metastasis is a major prognostic factor for esophageal squamous cell carcinoma (ESCC). In recent years, endoscopic mucosal resection (EMR) has been developed with excellent results for the treatment of the superficial ESCC. To make the EMR treatment successful, it is important to establish a good indicator to identify ESCC patients at a high risk of lymph node metastasis. In this study, we examined clinicopathological and immunohistochemical factors to investigate the factors involved in lymph node metastasis of ESCC invading to the submucosal layer (sm‐ESCC). Surgical specimens from 84 sm‐ESCC patients were examined. Among 84 sm‐ESCC patients, 33 (39.3%) had lymph node metastases. Clinicopathologically, tumor depth, lymphatic invasion and blood vessel invasion showed significant correlations with lymph node metastasis by univariate analysis. Tumor depth and lymphatic invasion showed significant correlations by multivariate analysis of these factors. Immunohistochemically, P53 accumulation was observed in 45 cases (53.6%), cyclin D1 overexpression in 25 (29.8%), and pRB in 65 (77.4%). P53 accumulation, cyclin D1 overexpression and MIB‐1 Labeling Index were significantly associated with lymph node metastasis by univariate analysis, and P53 accumulation showed a significant correlation with lymph node metastasis by multivariate analysis. Among tumor depth, lymphatic invasion and P53 accumulation, tumor depth and lymphatic invasion were significantly correlated with lymph node metastasis (P=0.0023 and P=0.0092, respectively) by multivariate analysis. These data suggest that tumor depth and lymphatic invasion can be considered as good indicators for lymph node metastasis among patients with sm‐ESCC. In addition, P53 accumulation could be helpful to identify the patients who need additional treatment after EMR.