title: Second reading of screening mammograms increases cancer detection and recall rates. Results in the Florence screening programme.
abstract: OBJECTIVE
  To assess double reading effectiveness in mammography screening.
  
  
  METHODS
  Retrospective study of 177,631 consecutive mammograms double read during 1998-2003.
  
  
  METHODS
  The Florence screening programme, involving 11 trained radiologists. Abnormalities reported by at least one reader prompted assessment.
  
  
  RESULTS
  The referral rate was 2.89% for the first reader, 3.15% for the second reader, and 3.59% for either reader. Of 713 total cancers detected, 43 were suspected only by the second reader (6.4% relative, 0.024% increase in absolute detection rate) and had a lower stage compared to the first reader (pTis-pT1b = 65.7 versus 52.0%): 41 were reviewed and classified (error type) as "minimal sign" in six, and "screening error" in 35 cases, or as BI-RADS 3 in one, 4a in 20, 4b in 13, and 4c in three cases. The second reading cost was 2.70 per woman examined, or 11,168 per additional cancer detected (versus 11,585 at a single reading).
  
  
  CONCLUSIONS
  Second reading is effective in detecting a limited number of additional cancer cases. Tumour stage (one-third over 1 cm in diameter) and review findings (high rate of "screening errors" and BI-RADS R4b-c categories) suggest that second reading detects small "difficult cases" as well as larger cancers missed due to fatigue or loss of attention. Second reading reduces screening specificity to a minor extent, and since cancer detection at second reading seems cost-effective the procedure is recommendable in routine practice.
authors.affiliation: Department of Diagnostic Imaging, Centro per lo Studio e la Prevenzione Oncologica, viale A. Volta 171, 50131 Florence, Italy. s.ciatto@cspo.it
authors.forename: S
authors.initials: S
authors.lastname: Ciatto
authors.forename: D
authors.initials: D
authors.lastname: Ambrogetti
authors.forename: R
authors.initials: R
authors.lastname: Bonardi
authors.forename: S
authors.initials: S
authors.lastname: Catarzi
authors.forename: G
authors.initials: G
authors.lastname: Risso
authors.forename: M
authors.initials: M
authors.lastname: Rosselli Del Turco
authors.forename: P
authors.initials: P
authors.lastname: Mantellini
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis*; D003362:Cost-Benefit Analysis; D003365:Costs and Cost Analysis; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007558:Italy; D008327:Mammography / Q000379:methods*; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014962:X-Ray Film