title: Evidence-based gallbladder cancer staging: changing cancer staging by analysis of data from the National Cancer Database.
abstract: BACKGROUND
  A recent revision of the American Joint Committee on Cancer (AJCC) staging for gallbladder cancer (6th Edition) involved some major changes. Most notably, T2N0M0 tumors were moved from stage II to stage IB; T3N1M0 disease was moved from stage III to stage IIB; and T4NxM0 (x = any) tumors were moved from stage IVA to stage III.
  
  
  METHODS
  In order to determine if these changes were justified by data, an analysis of the 10,705 cases of gallbladder cancer collected between 1989 and 1996 in the NCDB was performed. All patients had >5 year follow-up.
  
  
  RESULTS
  The staging according to the 6th Edition provided no discrimination between stage III and IV. Five-year survivals for stage IIA, IIB, III, and IV (6th Edition) were 7%, 9%, 3%, 2% respectively. The data from the National Cancer Database (NCDB) were used to derive a proposed new staging system that builds upon Edition 5 and had improved discrimination of stage groups over previous editions.
  
  
  CONCLUSIONS
  Changes in staging systems should be justified by data. Multicenter databases, including the NCDB, represent important resources for verification of evidence-based staging systems.
authors.affiliation: Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA. FongY@mskcc.org
authors.forename: Yuman
authors.initials: Y
authors.lastname: Fong
authors.forename: Lawrence
authors.initials: L
authors.lastname: Wagman
authors.forename: Mithat
authors.initials: M
authors.lastname: Gonen
authors.forename: James
authors.initials: J
authors.lastname: Crawford
authors.forename: William
authors.initials: W
authors.lastname: Reed
authors.forename: Richard
authors.initials: R
authors.lastname: Swanson
authors.forename: Charlie
authors.initials: C
authors.lastname: Pan
authors.forename: Jamie
authors.initials: J
authors.lastname: Ritchey
authors.forename: Andrew
authors.initials: A
authors.lastname: Stewart
authors.forename: Michael
authors.initials: M
authors.lastname: Choti
mesh_terms: D019992:Databases as Topic; D019317:Evidence-Based Medicine / Q000706:statistics & numerical data*; D005500:Follow-Up Studies; D005706:Gallbladder Neoplasms / Q000401:mortality / Q000473:pathology*; D006801:Humans; D009367:Neoplasm Staging / Q000706:statistics & numerical data; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D014481:United States / Q000453:epidemiology