Para-aortic lymph node micrometastasis in patients with node-negative biliary cancer.

BACKGROUND/AIMS The presence of para-aortic lymph node metastasis in biliary cancer negatively impacts prognosis. The present study aims to immunohistochemically identify and evaluate the clinical significance of para-aortic lymph node micrometastases in 66 patients who had undergone curative resection of biliary cancer. METHODS We used an antibody against cytokeratins 7 and 8 (CAM5.2) to immunostain 529 para-aortic lymph nodes that were negative according to conventional analysis from 66 patients with biliary cancer. RESULTS We detected CAM5.2-positive occult carcinoma cells in para-aortic lymph nodes from 3 (5%) of the 66 patients and in 3 (0.6%) of the 529 para-aortic lymph nodes. One of the 3 patients also had micrometastasis in the regional lymph nodes. All 3 patients with para-aortic lymph node micrometastasis are alive at 45, 48 and 90 months after surgery despite having locally advanced cancer. CONCLUSIONS Occult cancer cells were identified in para-aortic lymph nodes from 5% of patients with node-negative biliary cancer, yet these patients have survived over the long term. The presence of para-aortic nodal micrometastasis might not have an influence on survival. However, further studies using a greater number of patients are required to support this notion.