title: Spatial analysis of common gastrointestinal tract cancers in counties of Iran.
abstract: BACKGROUND
  Gastrointestinal tract cancers are among the most common cancers in Iran and comprise approximately 38% of all the reported cases of cancer. This study aimed to describe the epidemiology and to investigate spatial clustering of common cancers of the gastrointestinal tract across the counties of Iran using full Bayesian smoothing and Moran I Index statistics.
  
  
  METHODS
  The data of the national registry cancer were used in this study. Besides, indirect standardized rates were calculated for 371 counties of Iranand smoothed using Winbug 1.4 software with a full Bayesian method. Global Moran I and local Moran I were also used to investigate clustering.
  
  
  RESULTS
  According to the results, 75,644 new cases of cancer were nationally registered in Iran among which 18,019 cases (23.8%) were esophagus, gastric, colorectal, and liver cancers. The results of Global Moran's I test were 0.60 (P=0.001), 0.47 (P=0.001), 0.29 (P=0.001), and 0.40 (P=0.001) for esophagus, gastric, colorectal, and liver cancers, respectively. This shows clustering of the four studied cancers in Iran at the national level.
  
  
  CONCLUSIONS
  High level clustering of the cases was seen in northern, northwestern, western, and northeastern areas for esophagus, gastric, and colorectal cancers. Considering liver cancer, high clustering was observed in some counties in central, northeastern, and southern areas.
authors.affiliation: Departeman of Epidemiology, Research Center for Health Sciences, School of Health, Shiraz University of Medical Science, Shiraz, Iran E-mail : jhasanzad@sums.ac.ir.
authors.forename: Ali
authors.initials: A
authors.lastname: Soleimani
authors.forename: Jafar
authors.initials: J
authors.lastname: Hassanzadeh
authors.forename: Ali Ghanbari
authors.initials: AG
authors.lastname: Motlagh
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Tabatabaee
authors.forename: Elham
authors.initials: E
authors.lastname: Partovipour
authors.forename: Sareh
authors.initials: S
authors.lastname: Keshavarzi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hossein
mesh_terms: D000368:Aged; D001499:Bayes Theorem; D016000:Cluster Analysis; D003710:Demography; D005260:Female; D005500:Follow-Up Studies; D005770:Gastrointestinal Neoplasms / Q000453:epidemiology* / Q000473:pathology*; D006801:Humans; D015994:Incidence; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012042:Registries; D012307:Risk Factors; D062206:Spatial Analysis