Detection of micrometastases in histologically negative lymph nodes in esophageal cancer

Background. New molecular techniques may identify micrometastases in histologically negative lymph nodes and have an impact on the staging of esophageal cancer. We investigated the role of the reverse transcriptase–polymerase chain reaction (RT–PCR) assay to identify micrometastases in esophageal cancer. Methods. The RT–PCR assay to detect carcinoembryonic antigen (CEA) messenger ribonucleic acid (mRNA) was performed on lymph nodes from patients with esophageal cancer and benign esophageal disorders. The presence of CEA mRNA in lymph nodes was considered evidence of metastases. Results. Histopathologic study revealed metastases in 50 (41%) of 123 lymph nodes from 30 patients with esophageal cancer. All histologically positive lymph nodes contained CEA mRNA by RT–PCR. Of 73 histologically negative lymph nodes, 36 (49%) contained CEA mRNA, a significant increase compared with the histopathologic diagnosis (p< 0.001). Lymph nodes in patients with benign disease contained no CEA mRNA. In 10 patients, histologic stage was N0. Five of them were also negative by RT–PCR, and all are alive with only one recurrence. In the remaining 5 patients, RT–PCR was positive for occult lymph node metastases; 2 have died of disease, and 1 is alive with recurrent disease. Conclusions. In patients with esophageal cancer, RT–PCR detects more lymph node metastases than does histopathology. Initial follow-up suggests a positive RT–PCR with negative histologic findings may have poor prognostic implications. Further studies will be needed to confirm any clinical implications.