title: Tumor location does not impact long-term survival in patients with operable thoracic esophageal squamous cell carcinoma in China.
abstract: BACKGROUND
  The seventh edition of the American Joint Committee on Cancer staging system considers tumor location as a factor in staging esophageal squamous cell carcinoma (ESCC). However, more data are essential to test its efficacy. The purpose of this study is to assess whether tumor location should be included as a factor in staging of thoracic ESCC in Chinese patients.
  
  
  METHODS
  A retrospective review of 1,220 patients with ESCC who underwent complete resection between December 1996 and December 2008 was conducted. Survival was calculated by the Kaplan-Meier method, and the log-rank test was used to assess survival differences between groups. Subgroup analysis and the Cox proportional hazards model were used to further determine the impact of tumor location on overall survival.
  
  
  RESULTS
  The median survival times for patients with ESCC in the upper third, middle third, and lower third of the esophagus were 45.1 months, 62.9 months, and 39.2 months, respectively, with corresponding 5-year survival rates of 44.8%, 50.5%, and 45.6%, respectively (p=0.191). Subgroup analysis also demonstrated that tumor location did not determine survival prognosis. Multivariate Cox regression analysis suggested that being female (p=0.001), being young (p<0.001), having a lower grade of cell differentiation (p=0.030), T category (p<0.001), and N category (p<0.001) were independent factors favoring overall survival, whereas tumor location (p=0.295) and surgical approaches (p=0.521) were not independent factors impacting prognosis.
  
  
  CONCLUSIONS
  Staging of ESCC in the Chinese population should be simplified by omitting tumor location as a variable. More data from Asian populations are warranted to verify these results.
authors.affiliation: Department of Thoracic Surgery, Sun Yat-sen University Cancer Center, Guangzhou City, Guangdong Province, China.
authors.forename: Hao-Xian
authors.initials: HX
authors.lastname: Yang
authors.forename: Xue
authors.initials: X
authors.lastname: Hou
authors.forename: Qian-Wen
authors.initials: QW
authors.lastname: Liu
authors.forename: Lan-Jun
authors.initials: LJ
authors.lastname: Zhang
authors.forename: Jin-Geng
authors.initials: JG
authors.lastname: Liu
authors.forename: Peng
authors.initials: P
authors.lastname: Lin
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Fu
mesh_terms: D000367:Age Factors; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D002681:China; D004938:Esophageal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D016629:Esophagectomy; D004947:Esophagus / Q000473:pathology; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012737:Sex Factors