title: Bile duct invasion can be an independent prognostic factor in early stage hepatocellular carcinoma.
abstract: OBJECTIVE
  In hepatocellular carcinoma (HCC), bile duct invasion occurs far more rarely than vascular invasion and is not well characterized. In addition, the pathologic finding of bile duct invasion is not considered an independent prognostic factor for HCC following surgery. In this study, we determined the characteristics of HCC with bile duct invasion, and assessed the clinical significance of bile duct invasion.
  
  
  METHODS
  We retrospectively reviewed the medical records of 363 patients who underwent hepatic resection for HCC at Seoul National University Hospital (SNUH) from January 2009 to December 2011. Preoperative, operative, and pathological data were collected. The risk factors for recurrence and survival were analyzed. Subsequently, the patients were divided into 2 groups according to disease stage (American Joint Committee on Cancer/International Union Against Cancer 7(th) edition): early stage (T1 and 2) and advanced stage (T3 and 4) group; and risk factors in the sub-groups were analyzed.
  
  
  RESULTS
  Among 363 patients, 13 showed bile duct invasion on pathology. Patients with bile duct invasion had higher preoperative total bilirubin levels, greater microvascular invasion, and a higher death rate than those without bile duct invasion. In multivariate analysis, bile duct invasion was not an independent prognostic factor for survival for the entire cohort, but, was an independent prognostic factor for early stage.
  
  
  CONCLUSIONS
  Bile duct invasion accompanied microvascular invasion in most cases, and could be used as an independent prognostic factor for survival especially in early stage HCC (T1 and T2).
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Ye-Rang
authors.initials: YR
authors.lastname: Jang
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kwang-Woong
authors.initials: KW
authors.lastname: Lee
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Hyeyoung
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jeong-Moo
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Nam-Joon
authors.initials: NJ
authors.lastname: Yi
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyung-Suk
authors.initials: KS
authors.lastname: Suh
keywords: Bile duct invasion; Hepatocellular carcinoma