Histological features of lymph node metastasis in patients with biliary tract cancer

Abstract

The presence of lymph node (LN) metastases is an important prognostic factor in patients with biliary cancers. The aim of this study was to characterize systematically the morphological features of metastatic LNs in biliary cancers. Four hundred ninety-six LNs (including 112 para-aortic LNs) dissected from 47 patients with biliary cancer were examined. The diameter of the long axis (size) and the percent metastatic area relative to whole-node area were measured from histologic specimens. The average size of metastatic LNs (9.5 mm) was significantly larger than those without metastasis (6.5 mm; P < 0.01). The optimum cut-off size for positive LNs was >7.5 mm, but the sensitivity of this predictor of metastasis was low (60.8%). In general, metastatic area correlated significantly with the size of metastatic LNs (P = 0.023). Para-aortic LNs contained metastasis in 7.1% of cases, and only 25% of para-aortic LNs with a high ratio of metastatic area could be evaluated from preoperative CT scans. Although large LNs are highly suggestive of metastasis, poor detection of many small LNs with a low percentage of metastatic area can increase risk in patients with biliary tract cancer.