title: Overdiagnosis in mammographic screening for breast cancer in Europe: a literature review.
abstract: OBJECTIVE
  Overdiagnosis, the detection through screening of a breast cancer that would never have been identified in the lifetime of the woman, is an adverse outcome of screening. We aimed to determine an estimate range for overdiagnosis of breast cancer in European mammographic service screening programmes.
  
  
  METHODS
  We conducted a literature review of observational studies that provided estimates of breast cancer overdiagnosis in European population-based mammographic screening programmes. Studies were classified according to the presence and the type of adjustment for breast cancer risk (data, model and covariates used), and for lead time (statistical adjustment or compensatory drop). We expressed estimates of overdiagnosis from each study as a percentage of the expected incidence in the absence of screening, even if the variability in the age range of the denominator could not be removed. Estimates including carcinoma in situ were considered when available.
  
  
  RESULTS
  There were 13 primary studies reporting 16 estimates of overdiagnosis in seven European countries (the Netherlands, Italy, Norway, Sweden, Denmark, UK and Spain). Unadjusted estimates ranged from 0% to 54%. Reported estimates adjusted for breast cancer risk and lead time were 2.8% in the Netherlands, 4.6% and 1.0% in Italy, 7.0% in Denmark and 10% and 3.3% in England and Wales.
  
  
  CONCLUSIONS
  The most plausible estimates of overdiagnosis range from 1% to 10%. Substantially higher estimates of overdiagnosis reported in the literature are due to the lack of adjustment for breast cancer risk and/or lead time.
authors.affiliation: Statistician, Clinical and Descriptive Epidemiology Unit, ISPO – Cancer Research and Prevention Institute, Florence, Italy
authors.forename: Donella
authors.initials: D
authors.lastname: Puliti
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Duffy
authors.forename: Guido
authors.initials: G
authors.lastname: Miccinesi
authors.forename: Harry
authors.initials: H
authors.lastname: de Koning
authors.forename: Elsebeth
authors.initials: E
authors.lastname: Lynge
authors.forename: Marco
authors.initials: M
authors.lastname: Zappa
authors.forename: Eugenio
authors.initials: E
authors.lastname: Paci
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis*; D003951:Diagnostic Errors; D005060:Europe; D005260:Female; D006801:Humans; D008327:Mammography