title: Increased colorectal cancer incidence in Iran: a systematic review and meta-analysis.
abstract: BACKGROUND
  Colorectal cancer is the third most common cancer in Iran. The increasing trend of colorectal cancer incidence in Iran and the close relationship with the geographical location are the underlying reasons for this study.
  
  
  METHODS
  
  
  
  METHODS
  Eleven databases, including MEDLINE, EMBASE, SCOPUS, and four other databases, for articles in Persian were searched from April 2014 to October 2014. Additional data were obtained from an online survey of the Central Library of Tabriz Faculty of Medicine.
  
  
  METHODS
  In this systematic review and meta-analysis, we included studies reporting different measures of incidence, age-standardized incidence rates, and crude incidence rates. All rates (per 100,000 person-years) were standardized to the world standard population.
  
  
  METHODS
  A preliminary review of the title and abstracts of these articles was used to exclude any that were clearly irrelevant. The full text review determined whether the article was relevant to our topic. All the potentially relevant manuscripts were reviewed by two other investigators (S.D., M.G.). A total of 39 studies (10 Persian and 29 English articles) from different provinces and diverse areas of Iran, were analyzed in this study using comprehensive meta-analysis software. For accuracy studies, we used estimated rates for males and females with 95 % confidence intervals.
  
  
  RESULTS
  Age-standardized incidence rates were obtained based on the random effects model and were 8.16 (95 % CI: 6.64 to 9.68) and 6.17 (95 % CI: 5.01 to 7.32) for males and females, respectively. The random crude rates were 5.58 (95 % CI: 4.22 to 6.94) for males and 4.01 (95 % CI: 3.06 to 4.97) for females.
  
  
  CONCLUSIONS
  Colorectal cancer incidence rates rise due to individual and environmental risk factors as well as improvement in the registry system and increase in access to health services. A more executed organized and structured system for collecting cancer data, in all cities and rural areas of the country, is an essential priority.
authors.affiliation: Hematology and Oncology Research Center, Tabriz University of Medical Sciences, 51666114731, Tabriz, Iran. royadolatkhah@yahoo.com.
authors.forename: Roya
authors.initials: R
authors.lastname: Dolatkhah
authors.affiliation: Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. mhosseinsina@yahoo.com.
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Somi
authors.affiliation: Hematology and Oncology Research Center, Tabriz University of Medical Sciences, 51666114731, Tabriz, Iran. iraj_akermani@hotmail.com.
authors.forename: Iraj Asvadi
authors.initials: IA
authors.lastname: Kermani
authors.affiliation: Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. AS4007@yahoo.com.
authors.forename: Morteza
authors.initials: M
authors.lastname: Ghojazadeh
authors.affiliation: Road Traffic Injury Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. m.asghari862@gmail.com.
authors.forename: Mohamad Asghari
authors.initials: MA
authors.lastname: Jafarabadi
authors.affiliation: The University of Kansas Medical School-Molecular Medicine Laboratory, Kansas City, KS, USA. ffarassati@kumc.edu.
authors.forename: Faris
authors.initials: F
authors.lastname: Farassati
authors.affiliation: Hematology and Oncology Research Center, Tabriz University of Medical Sciences, 51666114731, Tabriz, Iran. saeed.dastgiri@gmail.com.
authors.forename: Saeed
authors.initials: S
authors.lastname: Dastgiri
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007492:Iran / Q000453:epidemiology; D008297:Male; D012042:Registries