title: Validation of the 7th AJCC/UICC staging system for gastric cancer and a proposal for a new TNM system based on a prognostic score: a retrospective multicenter study.
abstract: OBJECTIVE
  We validate the 7th American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging system for gastric cancer and propose a new staging system that reflects the prognostic significances of each of T and N category.
  
  
  METHODS
  Data from 5,957 patients who underwent curative gastrectomies from 2000 to 2007 at 4 university hospitals in Daegu Metropolitan city in Korea were analyzed for the validation of the 7th AJCC/UICC staging system for gastric cancer. The hazard ratios of the respective T and N categories were estimated and converted to weightings and summated to make prognostic score (P-score). Homogeneity and stage grouping were determined according to the P-scores.
  
  
  RESULTS
  In the 7th AJCC/UICC staging system for gastric cancer, poor discrimination was noted between stages IIB and IIIA (P = 0.152). In addition, heterogeneity in stage IIB (P = 0.021) and a small gap in 5-year survival rates (1.7%) between stages IA and IB were noted. A new proposed staging system was generated on the basis of P-scores and demonstrated more discrimination between stages and more homogeneity within stages. The new staging system reflects the different prognostic impacts of N3a and N3b.
  
  
  CONCLUSIONS
  Several controversial issues of the 7th AJCC/UICC staging system for gastric cancer were reconfirmed in the present analysis. The TNM system based on P-score appears to be more scientifically accurate than the 7th AJCC/UICC staging system for gastric cancer.
authors.affiliation: Department of Surgery, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Oh Kyoung
authors.initials: OK
authors.lastname: Kwon
authors.affiliation: Department of Surgery, Yeungnam University College of Medicine, Daegu, Korea.
authors.forename: Se Won
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Surgery, Catholic University of Daegu School of Medicine, Daegu, Korea.
authors.forename: Hyun-Dong
authors.initials: HD
authors.lastname: Chae
authors.affiliation: Department of Surgery, Keimyung University School of Medicine, Daegu, Korea.
authors.forename: Seung Wan
authors.initials: SW
authors.lastname: Ryu
authors.affiliation: Department of Surgery, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Ho Young
authors.initials: HY
authors.lastname: Chung
authors.affiliation: Department of Surgery, Yeungnam University College of Medicine, Daegu, Korea.
authors.forename: Sang Woon
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Biomedical Research Institute, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Won Kee
authors.initials: WK
authors.lastname: Lee
authors.affiliation: Department of Surgery, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Wansik
authors.initials: W
authors.lastname: Yu
keywords: Stomach neoplasms; TNM classification