title: Comparison of two diverse populations, British Columbia, Canada, and Ardabil, Iran, indicates several variables associated with gastric and esophageal cancer survival.
abstract: BACKGROUND
  Geographic variation and temporal trends in the epidemiology of esophageal and gastric cancers vary according to both tumor morphology and organ subsite. This study compares 1-year survival of gastric and esophageal cancers between two distinct populations: British Columbia (BC), Canada, and Ardabil, Iran.
  
  
  METHODS
  Data for invasive primary esophageal and gastric cancer patients were obtained from the population-based cancer registries for BC and Ardabil. The relative survival rate was calculated using WHO Statistical Information System (WHOSIS) life-tables for each country. Chi-square and Fisher's exact tests were used to compare survival differences between BC and Ardabil. T-tests, chi-square tests, and Fisher's exact test were used to compare patient characteristics and tumor factors between the populations.
  
  
  RESULTS
  The overall 1-year age-standardized relative survivals for gastric cancer were 48% and 21% in BC and Ardabil, respectively (p < 0.01). The overall 1-year age-standardized relative survival for esophageal cancer was 33% and 17% in BC and Ardabil, respectively (p < 0.05). Overall and separately for each gender, age group, tumor location, and histology, there was greater 1-year survival of the gastric cancer patients in BC compared to Ardabil. For esophageal cancer; patients under age 65, patients with tumors in the middle or upper third of esophagus, and patients with squamous cell carcinoma had significantly better survival in BC than in Ardabil.
  
  
  CONCLUSIONS
  Findings of this study point to differences in disease characteristics and patient factors, not solely differences in healthcare systems, as being responsible for the survival difference in these populations.
authors.affiliation: Cancer Control Research Program, BC Cancer Agency, Vancouver, Canada.
authors.forename: Morteza
authors.initials: M
authors.lastname: Bashash
authors.forename: Parvin
authors.initials: P
authors.lastname: Yavari
authors.forename: T Greg
authors.initials: TG
authors.lastname: Hislop
authors.forename: Amil
authors.initials: A
authors.lastname: Shah
authors.forename: Alireza
authors.initials: A
authors.lastname: Sadjadi
authors.forename: Masoud
authors.initials: M
authors.lastname: Babaei
authors.forename: Nhu
authors.initials: N
authors.lastname: Le
authors.forename: Angela
authors.initials: A
authors.lastname: Brooks-Wilson
authors.forename: Reza
authors.initials: R
authors.lastname: Malekzadeh
authors.forename: Chris
authors.initials: C
authors.lastname: Bajdik
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000401:mortality*; D000368:Aged; D001955:British Columbia / Q000453:epidemiology; D002170:Canada / Q000453:epidemiology; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000401:mortality*; D004938:Esophageal Neoplasms / Q000378:metabolism / Q000401:mortality*; D005260:Female; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000378:metabolism; D007492:Iran / Q000453:epidemiology; D008263:Macrophage Migration-Inhibitory Factors / Q000378:metabolism; D008297:Male; D009367:Neoplasm Staging; D011379:Prognosis; D012042:Registries; D013274:Stomach Neoplasms / Q000378:metabolism / Q000401:mortality*; D015996:Survival Rate; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D008263:Macrophage Migration-Inhibitory Factors; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D019746:Intramolecular Oxidoreductases; C515598:MIF protein, human