[Surgical strategies for middle and lower bile duct cancer]

R0 resectability is thought to be one of the important prognostic factors in bile duct cancer. To achieve R0 resection, accurate preoperative diagnosis is essential. However, intraoperative frozen-section diagnosis sometimes reveals positive ductal margins. It is known that nodular infiltrative tumors tend to extend to the subserosal layer. On the other hand, papillary tumors often have extensive intramural extension, the so-called intraepithelial spread. This type of extension remains difficult to diagnose preoperatively. Some investigators query the clinical significance of positive ductal margins with carcinoma in situ or severe dysplasia. However, even in such instances, local recurrence 5 years after the initial surgery was reported in several articles. Middle bile duct cancer often extends to the upper (hilar bile duct) and lower (intrapancreatic bile duct) sections of the bile duct. To achieve R0 resection, a variety of operative procedures should be considered. For example, hepatopancreatoduodenectomy is required in patients with broad tumor extension up to the hilar bile ducts. However, hilar bile duct resection can result in R0 resection for patients with limited tumor extension. Thus, appropriate operative procedures should be selected based on patients' organ function and other possible prognostic factors, such as lymph node metastases.