title: Predicting the probability of mortality of gastric cancer patients using decision tree.
abstract: BACKGROUND
  Gastric cancer is the fourth most common cancer worldwide. This reason motivated us to investigate and introduce gastric cancer risk factors utilizing statistical methods.
  
  
  OBJECTIVE
  The aim of this study was to identify the most important factors influencing the mortality of patients who suffer from gastric cancer disease and to introduce a classification approach according to decision tree model for predicting the probability of mortality from this disease.
  
  
  METHODS
  Data on 216 patients with gastric cancer, who were registered in Taleghani hospital in Tehran,Iran, were analyzed. At first, patients were divided into two groups: the dead and alive. Then, to fit decision tree model to our data, we randomly selected 20% of dataset to the test sample and remaining dataset considered as the training sample. Finally, the validity of the model examined with sensitivity, specificity, diagnosis accuracy and the area under the receiver operating characteristic curve. The CART version 6.0 and SPSS version 19.0 softwares were used for the analysis of the data.
  
  
  RESULTS
  Diabetes, ethnicity, tobacco, tumor size, surgery, pathologic stage, age at diagnosis, exposure to chemical weapons and alcohol consumption were determined as effective factors on mortality of gastric cancer. The sensitivity, specificity and accuracy of decision tree were 0.72, 0.75 and 0.74 respectively.
  
  
  CONCLUSIONS
  The indices of sensitivity, specificity and accuracy represented that the decision tree model has acceptable accuracy to prediction the probability of mortality in gastric cancer patients. So a simple decision tree consisted of factors affecting on mortality of gastric cancer may help clinicians as a reliable and practical tool to predict the probability of mortality in these patients.
authors.affiliation: Department of Basic Sciences, Faculty of Medicine, Gonabad University of Medical Sciences, Gonabad, Iran.
authors.forename: F
authors.initials: F
authors.lastname: Mohammadzadeh
authors.forename: H
authors.initials: H
authors.lastname: Noorkojuri
authors.forename: M A
authors.initials: MA
authors.lastname: Pourhoseingholi
authors.forename: S
authors.initials: S
authors.lastname: Saadat
authors.forename: A R
authors.initials: AR
authors.lastname: Baghestani
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003663:Decision Trees; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D011336:Probability; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000145:classification / Q000401:mortality*; D055815:Young Adult