title: Impact of Screening on Breast Cancer Mortality: The UK Program 20 Years On.
abstract: BACKGROUND
  With changes in diagnosis, treatment, and management of breast cancer since the mammography screening trials, there is a need to evaluate contemporary breast screening programs. A case-control study was set up to assess the current impact of attendance in the English Breast Screening Program on breast cancer mortality.
  
  
  METHODS
  Cancer registry cases who died from primary breast cancer ages 47 to 89 years in London in 2008 to 2009 (869 women) were matched to 1 or 2 general population controls (1,642 women) with no diagnosis of breast cancer at the time of the case's diagnosis, who were alive at the case's death. Cases and controls were matched for date of birth and screening area, and had been invited to breast screening at least once prior to the case's diagnosis. ORs were estimated using conditional logistic regression. Self-selection bias was addressed using contemporaneous attendance at the cervical screening program. Sensitivity analyses were undertaken to assess the likely effect of lead time bias.
  
  
  RESULTS
  Attendance at breast screening resulted in a breast cancer mortality reduction of 39% [OR, 0.61; 95% confidence interval (CI), 0.44-0.85] after self-selection correction. Attendance in the last 3 years prior to diagnosis resulted in a 60% mortality reduction (OR, 0.40; 95% CI, 0.31-0.51). Lead time bias effects were negligible.
  
  
  CONCLUSIONS
  Our results suggest that community breast screening programs provide their expected benefit in terms of reducing the risk of breast cancer death among women participating.
  
  
  CONCLUSIONS
  Mammography is an important tool for reducing breast cancer mortality and its impact could be increased by encouraging regular attendance.
authors.affiliation: Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, England.
authors.forename: Nathalie J
authors.initials: NJ
authors.lastname: Massat
authors.affiliation: Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, England.
authors.forename: Amanda
authors.initials: A
authors.lastname: Dibden
authors.affiliation: Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, England.
authors.forename: Dharmishta
authors.initials: D
authors.lastname: Parmar
authors.affiliation: Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, England.
authors.forename: Jack
authors.initials: J
authors.lastname: Cuzick
authors.affiliation: Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, England.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Sasieni
authors.affiliation: Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, England. s.w.duffy@qmul.ac.uk.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Duffy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000401:mortality; D016022:Case-Control Studies; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008403:Mass Screening; D008875:Middle Aged; D015996:Survival Rate; D006113:United Kingdom