title: Impact of the UK colorectal cancer screening pilot studies on incidence, stage distribution and mortality trends.
abstract: OBJECTIVE
  To assess the impact of the UK colorectal cancer guaiac faecal occult blood test screening pilot studies on incidence trends, stage distribution and mortality trends.
  
  
  METHODS
  Ecological study.
  
  
  METHODS
  Scotland and the West Midlands.
  
  
  METHODS
  We extracted anonymised colorectal cancer (ICD-10 C18-C20) registration (1982-2006) and death records (1982-2007), along with corresponding mid-year population estimates.
  
  
  METHODS
  Residents of the screening pilot areas, in the age group 50-69 years, were offered biennial guaiac faecal occult blood test screening from 2000 onwards. Screening was not offered routinely in non-pilot areas until the start of the roll-out of the national screening programmes in England and in Scotland in 2006 and 2007, respectively.
  
  
  METHODS
  We analysed trends in age-specific incidence and mortality rates, and Dukes' stage distribution. Within each country/region, we compared the screening pilot areas to non-screening pilot ('control') areas using Chi square tests and Poisson regression modelling.
  
  
  RESULTS
  Following the start of the screening pilots, as expected in the prevalent round of a new screening programme, in the pilot areas there was a short-lived increase in incidence of colorectal cancer among 50-69 year olds except for females in the West Midlands. A trend towards earlier stage and less advanced disease was also observed, with males showing significant increases in Dukes' A and corresponding decreases in Dukes' C in the screening pilot areas (all P < 0.03). With the exception of females in the West Midlands, mortality rates for colorectal cancer decreased significantly and at a faster rate in the populations invited for screening.
  
  
  CONCLUSIONS
  The existence of a natural control population not yet invited for screening provided a unique opportunity to assess whether the benefits of colorectal cancer screening, beyond the setting of a randomised controlled trial, could be detected using routinely collected statistics. Our analysis suggests that screening will fulfil its aim of reducing mortality from colorectal cancer.
authors.affiliation: Scottish Cancer Registry, Information Services Division, NHS National Services Scotland, Gyle Square, 1 South Gyle Crescent, Edinburgh EH12 9EB, UK. paula.mcclements@nhs.net
authors.forename: Paula L
authors.initials: PL
authors.lastname: McClements
authors.forename: Vichithranie
authors.initials: V
authors.lastname: Madurasinghe
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Thomson
authors.forename: Callum G
authors.initials: CG
authors.lastname: Fraser
authors.forename: Francis A
authors.initials: FA
authors.lastname: Carey
authors.forename: Robert J C
authors.initials: RJ
authors.lastname: Steele
authors.forename: Gill
authors.initials: G
authors.lastname: Lawrence
authors.forename: David H
authors.initials: DH
authors.lastname: Brewster
mesh_terms: D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000401:mortality / Q000473:pathology* / Q000517:prevention & control; D055088:Early Detection of Cancer / Q000379:methods / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010865:Pilot Projects; D012737:Sex Factors; D006113:United Kingdom / Q000453:epidemiology