title: TNM staging of colorectal cancer should be reconsidered by T stage weighting.
abstract: OBJECTIVE
  To verify that the T stage has greater weight than the N stage in the staging of colorectal cancer.
  
  
  METHODS
  Open data from the Surveillance, Epidemiology, and End Results program were reviewed and analyzed according to the T stage, N stage, and patients' observed survival (OS). The relative weights of the T and N stages were calculated by multiple linear regressions based on their impact on survival. Risk scores for 25 TN categories were then calculated from the T and N stage relative weights, and a rearranged tumor node metastasis (TNM) staging system was proposed via a cluster analysis of the TN scores.
  
  
  RESULTS
  Both T and N stages significantly affect the OS of patients with colorectal cancer. Moreover, the T stage has greater weight than the N stage in the TNM staging system of colorectal cancer. For colon cancer, the relative T and N stage weights were 0.58 and 0.42, respectively, and for rectal cancer, the relative T and N stage weights were 0.61 and 0.39, respectively. On the basis of cluster analysis of the TN scores, T1N1a was classified to stage I, and T2N1a-1b and T1N1b-2a were classified to stage II in our revised TNM staging system for both colon and rectal cancer. For colon cancer, T4bN0 was classified to stage IIIa, but for rectal cancer, it was classified to stage IIIb.
  
  
  CONCLUSIONS
  As the T stage affects colorectal cancer survival more significantly than the N stage, the TNM staging should be revised by relative T stage weight.
authors.affiliation: Jun Li, Jian-Wei Wang, Xian-Hua Fu, Su-Zhan Zhang, Ke-Feng Ding, Department of Surgical Oncology, Second Affiliated Hospital, and The Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Jun Li, Jian-Wei Wang, Xian-Hua Fu, Su-Zhan Zhang, Ke-Feng Ding, Department of Surgical Oncology, Second Affiliated Hospital, and The Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Bao-Cai
authors.initials: BC
authors.lastname: Guo
authors.affiliation: Jun Li, Jian-Wei Wang, Xian-Hua Fu, Su-Zhan Zhang, Ke-Feng Ding, Department of Surgical Oncology, Second Affiliated Hospital, and The Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Li-Rong
authors.initials: LR
authors.lastname: Sun
authors.affiliation: Jun Li, Jian-Wei Wang, Xian-Hua Fu, Su-Zhan Zhang, Ke-Feng Ding, Department of Surgical Oncology, Second Affiliated Hospital, and The Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Wang
authors.affiliation: Jun Li, Jian-Wei Wang, Xian-Hua Fu, Su-Zhan Zhang, Ke-Feng Ding, Department of Surgical Oncology, Second Affiliated Hospital, and The Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Xian-Hua
authors.initials: XH
authors.lastname: Fu
authors.affiliation: Jun Li, Jian-Wei Wang, Xian-Hua Fu, Su-Zhan Zhang, Ke-Feng Ding, Department of Surgical Oncology, Second Affiliated Hospital, and The Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Su-Zhan
authors.initials: SZ
authors.lastname: Zhang
authors.affiliation: Jun Li, Jian-Wei Wang, Xian-Hua Fu, Su-Zhan Zhang, Ke-Feng Ding, Department of Surgical Oncology, Second Affiliated Hospital, and The Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Graeme
authors.initials: G
authors.lastname: Poston
authors.affiliation: Jun Li, Jian-Wei Wang, Xian-Hua Fu, Su-Zhan Zhang, Ke-Feng Ding, Department of Surgical Oncology, Second Affiliated Hospital, and The Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Zhejiang University College of Medicine, Hangzhou 310009, Zhejiang Province, China.
authors.forename: Ke-Feng
authors.initials: KF
authors.lastname: Ding
mesh_terms: D016000:Cluster Analysis; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology*; D006801:Humans; D016014:Linear Models; D009367:Neoplasm Staging / Q000379:methods*; D011237:Predictive Value of Tests; D012307:Risk Factors; D018426:SEER Program; D016019:Survival Analysis; D013997:Time Factors; D014481:United States
keywords: Cluster analysis; Colorectal cancer; Neoplasm staging; Observational study; Survival analysis