title: Serosal invasion in TNM staging of mass-forming intrahepatic cholangiocarcinoma.
abstract: OBJECTIVE
  The Liver Cancer Study Group of Japan established a tumor-nodule-metastasis (TNM) staging system for mass-forming intrahepatic cholangiocarcinoma, with T determined by tumor number and size and vascular or serosal invasion. Serosal invasion is not considered in the designation established by the International Union Against Cancer.
  
  
  METHODS
  Sixty-three patients who underwent hepatic resection for mass-forming intrahepatic cholangiocarcinoma were investigated retrospectively, with the investigation including univariate and multivariate analyses of potential prognostic factors.
  
  
  RESULTS
  By log-rank test, tumor size more than 3.0 cm, vascular invasion, lymph node metastasis, intrahepatic metastasis, and involved resection margin, but not serosal invasion, were associated significantly with poor prognosis. Even in patients with serosal invasion, the postoperative outcome was much better in those without than in those with vascular invasion. Multivariate analysis identified vascular invasion, lymph node metastasis, and an involved resection margin as independent prognostic factors. When serosal invasion was excluded from tumor staging, the 5-year survival rates became more clearly stratified: 100% in those with stage I disease, 62% in those with stage II, 25% in those with stage III, and 7% for patients with stage IV.
  
  
  CONCLUSIONS
  Serosal invasion showed no survival impact after hepatic resection for mass-forming intrahepatic cholangiocarcinoma. When serosal invasion was omitted from the TNM staging proposed by the Liver Cancer Study Group of Japan, stratification of postoperative survival between stages was more effective.
authors.affiliation: Department of Hepato-Biliary-Pancreatic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Uenishi
authors.forename: Osamu
authors.initials: O
authors.lastname: Yamazaki
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hirohashi
authors.forename: Hiromu
authors.initials: H
authors.lastname: Tanaka
authors.forename: Shogo
authors.initials: S
authors.lastname: Tanaka
authors.forename: Seikan
authors.initials: S
authors.lastname: Hai
authors.forename: Shoji
authors.initials: S
authors.lastname: Kubo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D001653:Bile Ducts, Intrahepatic; D018281:Cholangiocarcinoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis