CT evaluation of para-aortic lymph node metastasis in biliary cancer patients

Objectives The extent of para-aortic lymph nodes (PANs) metastasis is equivalent to distant metastases in patients with biliary carcinoma. Accurate preoperative assessment of PANs metastasis has a crucial impact on surgical indication. In this retrospective study, we evaluated whether computed tomography (CT) scans were useful for diagnosing PANs metastases and excluding patients with PANs metastases from surgical indication. Methods Between March 1999 and November 2003, 57 patients with biliary carcinoma underwent radical lymphadenectomy or surgical biopsy of PANs, nine of whom was diagnosed as having positive PANs microscopically. All patients had undergone abdominal CT scans before surgery. To diagnose PANs metastases, we used the following diagnostic criteria. 1) Size: when lymph nodes were greater than 12 mm, 10 mm, 8 mm or 6mm in diameter in long or short axis diameter, the nodes were considered metastatic. 2) Shape and size: when the axial ratio of a lymph node was greater than 0.5, 0.7, 1.0, and the maximum diameter in the long or short axis was greater than 12 mm, 10 mm, 8 mm, or 6mm the node was considered metastatic. 3) Internal structure: if the internal structure of a PANs was heterogeneous, the node was