title: A description of age, sex, and site distributions of colon carcinoma in three geographic areas.
abstract: BACKGROUND
  Site of the carcinoma within the colon in relation to age and sex may provide clues into the etiology of the disease. Incidence of colon carcinoma by age, sex, and tumor site at a population-based level are reported infrequently. The goal of this study was to describe the distribution of colon carcinoma (excluding cancers of the rectosigmoid junction and rectum) by age at diagnosis, sex, and site of the tumor within the colon. These factors were also evaluated in conjunction with disease stage at the time of diagnosis.
  
  
  METHODS
  Data from three geographically distinct populations were used to describe rates of colon carcinoma and the distribution of tumors by age, tumor site, and stage at diagnosis. All colon carcinoma cases diagnosed within a 3-year period within the areas are included.
  
  
  RESULTS
  Approximately 50% of all cancers in men and greater than 50% of cancers in women were in the proximal segment of the colon. Men who were diagnosed prior to age 50 and both men and women diagnosed at age 70 or older had predominantly proximal cancers. People with proximal cancers and people diagnosed prior to age 50 were more likely to have more advanced disease.
  
  
  CONCLUSIONS
  Both men and women have more proximal cancers with advancing age, which are associated with more advanced disease. Observed trends in cancer site distributions could reflect screening practices, environmental and genetic factors, or a combination of these variables.
authors.affiliation: Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Slattery
authors.forename: G D
authors.initials: GD
authors.lastname: Friedman
authors.forename: J D
authors.initials: JD
authors.lastname: Potter
authors.forename: S
authors.initials: S
authors.lastname: Edwards
authors.forename: B J
authors.initials: BJ
authors.lastname: Caan
authors.forename: W
authors.initials: W
authors.lastname: Samowitz
mesh_terms: D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D003110:Colonic Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012042:Registries; D012737:Sex Factors; D014481:United States / Q000453:epidemiology