title: Evaluation of the seventh edition of the tumour, node, metastasis (TNM) classification for colon cancer in two nationwide registries of the United States and Japan.
abstract: OBJECTIVE
  The new TNM classification is currently being implemented. We evaluated the TNM-7 staging system based on the two nationwide colon cancer registries in the United States and Japan to clarify whether this system better stratifies patients' prognoses than the TNM-6 did and to determine whether stratification can be effectively simplified.
  
  
  METHODS
  The Surveillance, Epidemiology, and End Results population-based data from 1988 to 2001 for 50139 colon cancer patients and the multi-institutional registry data from the Japanese Society for Cancer of the Colon and Rectum from 1984 to 1994 for 10754 patients were analysed. We devised a modified version of the TNM-7 staging system to allow simpler classification of the TN categories and compared the TNM-6, TNM-7, modified TNM-7, and the Dukes staging system based on survival curves and objective statistical tests such as likelihood ratio χ(2) tests, Akaike's information criterion, and Harrell's c-index.
  
  
  RESULTS
  The TNM-7 was superior to the TNM-6 in all objective statistical tests in the United States (c-index; 0.700 vs 0.696, P<0.001) as well as in the Japan data sets (0.732 vs 0.729, P=0.035). The modified TNM-7 is much simpler, but it nevertheless showed similar values to those of the original TNM-7 (c-index; the United States 0.702, Japan 0.733).
  
  
  CONCLUSIONS
  The new TNM-7 is complicated but better at stratifying patients than the TNM-6 in the United States and Japan, and could be effectively simplified.
authors.affiliation: Department of Surgery, National Defense Medical College, Saitama, Japan. yhashi@ndmc.ac.j
authors.forename: Y
authors.initials: Y
authors.lastname: Hashiguchi
authors.forename: K
authors.initials: K
authors.lastname: Hase
authors.forename: K
authors.initials: K
authors.lastname: Kotake
authors.forename: H
authors.initials: H
authors.lastname: Ueno
authors.forename: E
authors.initials: E
authors.lastname: Shinto
authors.forename: H
authors.initials: H
authors.lastname: Mochizuki
authors.forename: J
authors.initials: J
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Sugihara
mesh_terms: D000368:Aged; D003110:Colonic Neoplasms / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D007564:Japan; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000706:statistics & numerical data*; D011379:Prognosis; D012042:Registries / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D018426:SEER Program / Q000706:statistics & numerical data; D014481:United States