Carcinoma of the extrahepatic bile duct: Mode of spread and its prognostic implications

Background/Aims: The postoperative course of patients with bile duct carcinoma after surgical resection remains dismal. The purpose of this study was to examine the mode of spread from the original site of the carcinoma and its prognostic significance. Methodology: A total of 46 Japanese patients with extrahepatic bile duct carcinoma who underwent surgical resection from January 1976 to August 1995 were retrospectively reviewed. Results: Out of 24 patients with upper bile duct carcinoma, 16 (67%) were papillary or well differentiated tubular adenocarcinoma of the polypoid or nodular type on gross configuration, whereas 7 of 11 patients (64%) with lower bile duct carcinoma had moderately differentiated tubular adenocarcinoma or poorly differentiated adenocarcinoma of the annular constrictive or diffusely infiltrating type (p < 0.01). A noteworthy feature was perineural invasion (18/24, 75%) in the former group. Lymphatic permeation and venous invasion were seen in 50% and 38% of the former group and these were present in 73%, and in 73% of the latter (p < 0.01). Lymph node metastasis was most frequent in patients with lower bile duct carcinoma (5/11, 45%). Periductal spread along the bile duct toward the liver was more frequent and extensive in the infiltrating type than in the polypoid, nodular, or annullar constrictive type. Carcinoma of the polypoid type often extended along the mucosa and rarely through the periductal layer. The mean distance between the edge of carcinoma invasion estimated by cholangiography and that proved by histology on the resected specimens was 6.1 ± 6.1 mm in the hepatic and 6.2 ± 9.1 mm in the duodenal direction. In all 11 patients with lower bile duct carcinoma, surgical margins were free of cancer cells, while they were affected by malignant cells in 17 of 24 patients with upper bile duct carcinoma. Univariate log-rank analysis showed that venous invasion, perineural infiltration, and the presence or absence of cancer cells at the cut edge of the bile duct in the hepatic direction and at the resection margins in the transverse direction, were significant prognostic factors. Multivariate Cox regression analysis revealed that cancer cells at the edge of the bile duct in the hepatic direction constitute a significant and independent prognostic variant. Conclusions: Extrahepatic bile duct carcinoma should be excised to a distance of 1.5 cm from the edge of the carcinoma as estimated on cholangiography to achieve cancer-free margins, especially at the resected margins in the hepatic direction.