Pathological appraisal of lines of resection for bile duct carcinoma

Background: The aim of this study was to determine the most appropriate line of resection for extrahepatic bile duct carcinoma. Methods: A retrospective review was carried out of 253 resected specimens of extrahepatic bile duct carcinoma. Carcinomas were classified histologically as invasive or non-invasive in addition to assessment of the resection margin. Results: Tumour was present microscopically at the resection margin in 80 (31.6 per cent) of 253 cases, with 46 showing marginal involvement by non-invasive carcinoma, 20 showing invasive carcinoma at a margin, and 14 showing both. Involvement of the resection margin by invasive carcinoma was encountered only when the margin was shorter than 10 mm, whereas non-invasive carcinoma was encountered even when the margin length reached 40 mm. The observed length of microscopic extension of invasive carcinoma beyond the macroscopically evident tumour mass was limited to 10.0 mm. Median microscopic extension of non-invasive carcinoma beyond the mass was 10 mm (75th percentile 19.5 and 14.5 mm in proximal and distal directions respectively; maximum 52 mm). Margins of 20 mm could be assured to be negative proximally in 89.0 per cent of cases and distally in 93.8 per cent. Conclusion: For eradication of invasive extrahepatic bile duct carcinoma, a 10-mm margin is required. However, additional removal of any non-invasive component requires a 20-mm margin. These guidelines should be followed in any operation performed with curative intent.