“…In previous studies, the prognostic factors for extrahepatic bile duct cancer after surgical resection have been reported to be the depth of invasion, pancreatic invasion, duodenal invasion, perineural invasion, lymph node metastasis, the resection margin status and the TNM stage [8,14,17,18,19,20]. In the present study, multivariate analysis showed that the histologic grade and the postoperative CA 19-9 level were independent prognostic factors for OS.…”