Significance of immunohistochemical nodal micrometastasis as a prognostic indicator in potentially curable oesophageal carcinoma

Abstract

Abstract Background The number of positive lymph nodes is an important prognostic predictor in patients with oesophageal cancer. However, the significance of nodal micrometastasis in patients with overt nodal metastasis is unknown. The aim of this study was to clarify the clinical implications of nodal micrometastasis in patients undergoing curative oesophagectomy for oesophageal cancer. Methods Cervical, mediastinal and abdominal lymph nodes systematically removed from 104 patients with oesophageal cancer were examined immunohistochemically to detect cells that stained positively for cytokeratins with the monoclonal antibody cocktail AE1/AE3. The postoperative course and survival rates were compared among patients with and without micrometastases, after numerical classification of overt metastatic nodes (none, between one and four, five or more). Results Univariate analysis showed T stage, nodal micrometastasis and number of overt nodal metastases to be significant prognostic factors after oesophagectomy. Multivariate analysis revealed nodal micrometastasis and number of overt nodal metastases to be independent prognostic factors. The presence of micrometastases had a significant adverse effect on postoperative survival in patients with no overt metastasis and in patients with one to four overt metastatic nodes, but no such impact in patients with five or more overt metastatic nodes. Conclusion Assessment of nodal status by both histological examination for overt metastases and immunohistochemical examination for micrometastases is useful in stratifying patients undergoing curative oesophagectomy.