Significance of immunohistochemically demonstrated micrometastases to lymph nodes in esophageal cancer with histologically negative nodes

Background. We examined the prevalence, patterns, and clinical significance of nodal micrometastases in patients with esophageal cancer. Methods. Cervical, mediastinal, and abdominal lymph nodes systematically removed from 37 patients without conventional histologic evidence of lymph node metastasis from esophageal squamous cell carcinoma were immunohistochemically examined to detect cells that were stained for cytokeratins by the monoclonal antibody cocktail AE1/AE3 Postoperative care and survival were compared in cases with and without such micrometastases. Results. Nodal micrometastases were found in 14 of 37 patients (38%). Among these patients, 9, 7, and 4 had micromdastases to abdominal, mediastinal, and cervical lymph nodes, respectively. Postoperative tumor recurrence was significantly more frequent in patients with micrometastases (50%) than in those without (9%, P =.008). Overall and relapse-free survival in the former group was significantly worse than in the latter group (P =.042 and P =. 002, respectively). Nodal micrometastases had an independent prognostic importance for relapse-free survival as determined by multivariate analysis. Conclusions. Metastatic tumor cells are frequently present in lymph nodes, even in patients without histologic evidence of nodal metastasis from esophageal cancer. Nodal micrometastases indicates a poorer prognosis after a curative esophagectomy procedure in histologically node-negative cases.