title: Use of the spatial scan statistic to identify geographic variations in late stage colorectal cancer in California (United States).
abstract: OBJECTIVE
  To identify geographic variations in colorectal cancer by stage at diagnosis in California using a descriptive analysis coupled with a spatial analysis and to discuss methodological considerations concerning the spatial statistical method.
  
  
  METHODS
  We analyzed 59,076 colorectal cancer cases diagnosed in California from 1996 to 2000 by logistic regression and by a spatial scan statistic to identify areas with a higher and lower relative risk of late-stage colorectal cancer.
  
  
  RESULTS
  In California, 57% of overall cases of colorectal cancer were diagnosed at a late stage. Californians diagnosed with late-stage colorectal cancer were more likely to be Hispanic and living in areas of lower socioeconomic status. The spatial scan identified two areas where the observed number of late-stage cancer was different than the number expected from the distribution in the rest of the state.
  
  
  CONCLUSIONS
  Spatial scan analyses can complement descriptive statistics, but results must be interpreted with consideration of factors that affect the ability to detect meaningful differences such as the number of events observed, accuracy in geocoding rural versus urban addresses, and the difficulty of adjusting for covariates.
authors.affiliation: Centers for Disease Control and Prevention, 4770 Buford Hwy NE, Mailstop K55, Atlanta, GA 30341-3717, USA. lpollack@cdc.gov
authors.forename: Lori A
authors.initials: LA
authors.lastname: Pollack
authors.forename: Carol A
authors.initials: CA
authors.lastname: Gotway
authors.forename: Janet H
authors.initials: JH
authors.lastname: Bates
authors.forename: Arti
authors.initials: A
authors.lastname: Parikh-Patel
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Richards
authors.forename: Laura C
authors.initials: LC
authors.lastname: Seeff
authors.forename: Holly
authors.initials: H
authors.lastname: Hodges
authors.forename: Sidibe
authors.initials: S
authors.lastname: Kassim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D008297:Male; D008875:Middle Aged; D044469:Racial Groups; D012959:Socioeconomic Factors