title: The impact of tumor cell differentiation on survival of patients with resectable esophageal squamous cell carcinomas.
abstract: BACKGROUND
  The current American Joint Committee on Cancer staging system considers tumor cell differentiation grade to be a factor in the staging of esophageal squamous cell carcinoma (ESCC) in pathologic T0-3N0M0 cases. However, more data are essential to test its efficacy. We sought to investigate the tumor-node-metastasis categories for which tumor cell grade might affect overall survival in Chinese patients.
  
  
  METHODS
  We conducted a retrospective review of 1,220 patients with ESCC who underwent complete resection between December 1996 and December 2008. Survival was calculated by the Kaplan-Meier method, and the log-rank test was used to assess differences in survival between groups. Subgroup analyses and the Cox proportional hazards model were used to further determine the effect of tumor cell grade on overall survival.
  
  
  RESULTS
  The 5-year survival rates for the G1, G2, and G3 groups of pathologic T2N0M0 ESCC cases were 80.1, 61.9, and 47.4%, respectively (p = 0.015), and these rates in the pathologic T3N0M0 ESCC cases were 66.7, 61.7, and 41.2%, respectively (p = 0.020). However, the differences in the survival of the different tumor cell grade groups of the pathologic T1N0M0 (p = 0.198) and the node positive categories (p = 0.063) were not statistically significant. Multivariate Cox regression analysis confirmed that tumor cell grade independently affected the overall survival of patients with pathologic T2-3N0M0 ESCC.
  
  
  CONCLUSIONS
  The staging of ESCC in the Chinese population should be simplified by omitting tumor cell grade as a variable in patients with pathologic T1N0M0 disease. More data are needed to verify our results.
authors.affiliation: Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, People's Republic of China.
authors.forename: Xue
authors.initials: X
authors.lastname: Hou
authors.forename: Yang-Kui
authors.initials: YK
authors.lastname: Gu
authors.forename: Xue-Wen
authors.initials: XW
authors.lastname: Liu
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Fu
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Lan-Jun
authors.initials: LJ
authors.lastname: Zhang
authors.forename: Rong-Zhen
authors.initials: RZ
authors.lastname: Luo
authors.forename: Peng
authors.initials: P
authors.lastname: Lin
authors.forename: Hao-Xian
authors.initials: HX
authors.lastname: Yang
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000401:mortality* / Q000556:secondary* / Q000601:surgery; D002454:Cell Differentiation; D004938:Esophageal Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D016629:Esophagectomy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate