title: Summary of the evidence of breast cancer service screening outcomes in Europe and first estimate of the benefit and harm balance sheet.
abstract: OBJECTIVE
  To construct a European 'balance sheet' of key outcomes of population-based mammographic breast cancer screening, to inform policy-makers, stakeholders and invited women.
  
  
  METHODS
  From the studies reviewed, the primary benefit of screening, breast cancer mortality reduction, was compared with the main harms, over-diagnosis and false-positive screening results (FPRs).
  
  
  RESULTS
  Pooled estimates of breast cancer mortality reduction among invited women were 25% in incidence-based mortality studies and 31% in case-control studies (38% and 48% among women actually screened). Estimates of over-diagnosis ranged from 1% to 10% of the expected incidence in the absence of screening. The combined estimate of over-diagnosis for screened women, from European studies correctly adjusted for lead time and underlying trend, was 6.5%. For women undergoing 10 biennial screening tests, the estimated cumulative risk of a FPR followed by non-invasive assessment was 17%, and 3% having an invasive assessment. For every 1000 women screened biennially from age 50-51 until age 68-69 and followed up to age 79, an estimated seven to nine lives are saved, four cases are over-diagnosed, 170 women have at least one recall followed by non-invasive assessment with a negative result and 30 women have at least one recall followed by invasive procedures yielding a negative result.
  
  
  CONCLUSIONS
  The chance of saving a woman's life by population-based mammographic screening of appropriate quality is greater than that of over-diagnosis. Service screening in Europe achieves a mortality benefit at least as great as the randomized controlled trials. These outcomes should be communicated to women offered service screening in Europe.
authors.affiliation: Clinical and Descriptive Epidemiology Unit, ISPO, Cancer Prevention and Research Unit, 50144 Florence, Italy. e.paci@ispo.toscana.it
authors.forename: Eugenio
authors.initials: E
authors.lastname: Paci
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis*; D055088:Early Detection of Cancer; D005060:Europe; D005260:Female; D006801:Humans; D008327:Mammography; D008875:Middle Aged