title: Depth of tumor invasion better predicts prognosis than the current American Joint Committee on Cancer T classification for distal bile duct carcinoma.
abstract: BACKGROUND
  The American Joint Committee on Cancer (AJCC) T classification system for cholangiocarcinoma does not take into account the unique pathologic features of the bile duct. As such, the current AJCC T classification for distal cholangiocarcinoma may be inaccurate.
  
  
  METHODS
  A total of 147 patients with distal cholangiocarcinoma were identified from a single institution database. The prognostic importance of depth of tumor invasion relative to the AJCC T classification system was assessed.
  
  
  RESULTS
  The AJCC T classification was T1 (n = 11, 7.5%), T2 (n = 6, 4.1%), T3 (n = 73, 49.7%), or T4 (n = 57, 38.8%). When cases were analyzed according to depth of tumor invasion, most lesions were > or =5 mm (<5 mm, 9.5%; range, 5-12, 51.0%; >12 mm, 39.5%). The AJCC T classification was not associated with survival outcome (median survival, T1, 40.1 months; T2, 14.8 months; T3, 16.5 months; T4, 20.2 months; P = .17). In contrast, depth of tumor invasion was associated with a worse outcome as tumor depth increased (median survival, <5 mm, not reached; range, 5-12, 28.9 months; >12 mm, 12.9 months; P = .001). On multivariate analyses, tumor depth remained the factor most associated with outcome (<5 mm; hazard ratio [HR] = referent vs 5-12 mm; HR = 3.8 vs >12 mm; HR = 6.7 mm; P = .001).
  
  
  CONCLUSIONS
  The AJCC T classification for distal cholangiocarcinoma does not accurately predict prognosis. Depth of the bile duct carcinoma invasion is a better alternative method to determine prognosis and should be incorporated into the pathologic assessment of resected distal cholangiocarcinoma.
authors.affiliation: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.
authors.forename: Seung-Mo
authors.initials: SM
authors.lastname: Hong
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Pawlik
authors.forename: Hyungjun
authors.initials: H
authors.lastname: Cho
authors.forename: Bhuvnesh
authors.initials: B
authors.lastname: Aggarwal
authors.forename: Michael
authors.initials: M
authors.lastname: Goggins
authors.forename: Ralph H
authors.initials: RH
authors.lastname: Hruban
authors.forename: Robert A
authors.initials: RA
authors.lastname: Anders
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000145:classification* / Q000401:mortality / Q000473:pathology; D001653:Bile Ducts, Intrahepatic; D018281:Cholangiocarcinoma / Q000145:classification* / Q000401:mortality / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D016019:Survival Analysis