The significances of lymph node micrometastasis and its correlation with E-cadherin expression in pT1-T3N0 gastric adenocarcinoma

Background: Recently, micrometastasis (MM) in the lymph node in gastric cancer has been detected by cytokeratin immunostaining. However, clinical significance of MM and its relationship with reduced expression of E-cadherin in primary lesion have not been well studied. Methods: The 4,990 lymph nodes from 184 pT1 similar to T3N0 patients from 1995 to 2000 at Korea University Hospital were immunostained with the anticytokeratin AE1/3 antibody for detection of micometastasis. The primary lesions were also immunostained for E-cadherin expression. Results: MM in the lymph node of gastric cancer was found in 131 (2.6%) of total dissected nodes, and 31 of 184 patients (16.8%) were shown to have MM. The MM was significantly correlated with the depth of invasion, tumor size, operation method, Lauren classification, lymphovascular invasion and loss of E-cadherin expression in primary tumor. On multivariate analysis, the independent risk factors for MM were the depth of invasion and loss of E-cadherin expression. The patients with MM had significantly lower 5-year overall and disease free survival rate than those without MM. Conclusion: Lymph node MM in histologically node-negative gastric cancer was significantly correlated with poor 5-year survival rate. The determination of E-cadherin expression in primary gastric tumor may be useful in prediction of the MM.