“…Residual invasive carcinoma at the ductal resection margins (median survival time, 12‐21 months) has been reported to influence patient survival after surgical resection for extrahepatic cholangiocarcinoma more adversely than residual carcinoma in situ (median survival time, 29‐99 months) 26, 27, 28, 31, 32, 34, 38. Several research groups reported that survival following resection was comparable between patients who had negative ductal margins (median survival time, 33‐55 months) and those who had positive ductal margins with carcinoma in situ (median survival time, 37‐99 months) 26, 27, 28, 31, 32, 35. Although residual carcinoma in situ at the ductal margins does not have a strong adverse effect on survival in patients with extrahepatic cholangiocarcinoma, it may result in late local recurrence 26, 27, 28, 29, 31, 32, 34, 36, 53, 54, 55, 56, 57…”