title: Survival analysis of patients with esophageal cancer using parametric cure model.
abstract: OBJECTIVE
  Esophageal cancer is a major cause of mortality and morbidity in the Caspian littoral north-eastern part of Iran. The aim of this study was to calculate cure function as well as to identify the factors that are related to this function among patients with esophageal cancer in this geographical area.
  
  
  METHODS
  Three hundred fifty nine cases of esophageal cancer registered in the Babol cancer registry during the period of 1990 to 1991 (inclusive) were followed up for 15 years up to 2006. Parametric cure model was used to calculate cure fraction and investigate the factors responsible for probability of cure among patients.
  
  
  RESULTS
  Sample of subjects encompassed 62.7% men and 37.3% women, with mean ages of diagnosis was 60.0 and 55.3 years, respectively. The median survival time reached about 9 months and estimated survival rates in 1, 3, and 5 years following diagnosis were 23%, 15% and 13%, respectively. Results show the family history affects the cured fraction independently of its effect on early outcome and has a significant effect on the probability of uncured. The average cure fraction was estimated to be 0.10.
  
  
  CONCLUSIONS
  As the proportionality assumption of Cox model does not meet in certain circumstances, a parametric cure model can provide a better fit and a better description of survival related outcome.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mahboube
authors.initials: M
authors.lastname: Rasouli
authors.forename: Mahmood Reza
authors.initials: MR
authors.lastname: Ghadimi
authors.forename: Mahmood
authors.initials: M
authors.lastname: Mahmoodi
authors.forename: Kazem
authors.initials: K
authors.lastname: Mohammad
authors.forename: Hojjat
authors.initials: H
authors.lastname: Zeraati
authors.forename: Mostafa
authors.initials: M
authors.lastname: Hosseini
mesh_terms: D004938:Esophageal Neoplasms / Q000401:mortality* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012042:Registries; D016019:Survival Analysis; D015996:Survival Rate; D016896:Treatment Outcome