Clinicopathological analysis and prognosis of extrahepatic bile duct cancer with a microscopic positive ductal margin

Background The fate of a microscopic positive ductal margin (MPDM) of extrahepatic bile duct (EHBD) cancer is unclear. The purpose of this study was to analyse the clinicopathological features of EHBD cancer with MPDM and to identify the prognostic factors associated with survival. Methods Between 1995 and 2007, a retrospective analysis of 464 patients who had undergone surgical resection for EHBD cancer was conducted. Clinicopathological factors likely to influence survival were assessed using univariate and multivariate analysis. Results One hundred twenty-four patients had MPDM which included invasive carcinoma (IC) (n =85) and carcinoma in situ (CIS)/ high-grade dysplasia (HGD) (n = 39). The median survival (MS) of R0, R1 as CIS/ HGD, and R1 as IC were 41 months, 29 months, and 18 months, respectively. Adverse prognostic factors were 'IC' on the resection margin [HR = 1.66, 95% confidence intervals (CIs) 1.06-2.59, P = 0.026], and no use of adjuvant chemoradiotherapy (HR = 1.57, 95% CIs 1.04-2.39, P = 0.033). Adjuvant chemoradiotherapy was beneficial in patients with MPDM as IC (5-year survival rate 19.7 compared with 2.8%, P = 0.011). Conclusions The presence of MPDM is an important prognostic factor in EHBD cancer. When a ductal resection margin is positive, discrimination between 'IC' and 'CIS/ HGD' is important.