title: Cross-national comparison of screening mammography accuracy measures in U.S., Norway, and Spain.
abstract: OBJECTIVE
  To compare accuracy measures for mammographic screening in Norway, Spain, and the US.
  
  
  METHODS
  Information from women aged 50-69 years who underwent mammographic screening 1996-2009 in the US (898,418 women), Norway (527,464), and Spain (517,317) was included. Screen-detected cancer, interval cancer, and the false-positive rates, sensitivity, specificity, positive predictive value (PPV) for recalls (PPV-1), PPV for biopsies (PPV-2), 1/PPV-1 and 1/PPV-2 were computed for each country. Analyses were stratified by age, screening history, time since last screening, calendar year, and mammography modality.
  
  
  RESULTS
  The rate of screen-detected cancers was 4.5, 5.5, and 4.0 per 1000 screening exams in the US, Norway, and Spain respectively. The highest sensitivity and lowest specificity were reported in the US (83.1 % and 91.3 %, respectively), followed by Spain (79.0 % and 96.2 %) and Norway (75.5 % and 97.1 %). In Norway, Spain and the US, PPV-1 was 16.4 %, 9.8 %, and 4.9 %, and PPV-2 was 39.4 %, 38.9 %, and 25.9 %, respectively. The number of women needed to recall to detect one cancer was 20.3, 6.1, and 10.2 in the US, Norway, and Spain, respectively.
  
  
  CONCLUSIONS
  Differences were found across countries, suggesting that opportunistic screening may translate into higher sensitivity at the cost of lower specificity and PPV.
  
  
  CONCLUSIONS
  • Positive predictive value is higher in population-based screening programmes in Spain and Norway. • Opportunistic mammography screening in the US has lower positive predictive value. • Screening settings in the US translate into higher sensitivity and lower specificity. • The clinical burden may be higher for women screened opportunistically.
authors.affiliation: Department of Epidemiology and Evaluation, IMIM (Hospital del Mar Medical Research Institute), Pg Marítim 25-29, 08003, Barcelona, Spain.|Research Network on Health Services in Chronic Diseases (REDISSEC), Madrid, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Domingo
authors.affiliation: Department of Screening, Cancer Registry of Norway, P.O. 5313, Majorstua, 0304, Oslo, Norway.|Faculty of Health Science, Oslo and Akershus University College of Applied Sciences, P.O. 4, St. Olavs Plass, 0130, Oslo, Norway.
authors.forename: Solveig
authors.initials: S
authors.lastname: Hofvind
authors.affiliation: Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, 604 Blockley Hall, 423 Guardian Dr, Philadelphia, PA, 19104, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Hubbard
authors.affiliation: Department of Screening, Cancer Registry of Norway, P.O. 5313, Majorstua, 0304, Oslo, Norway.|National Advisory Unit for Women's Health, Oslo University Hospital, Rikshospitalet, P.O. 4950, Nydalen, 0424, Oslo, Norway.
authors.forename: Marta
authors.initials: M
authors.lastname: Román
authors.affiliation: Department of Biostatistics, School of Public Health, University of Washington, F-600, Health Sciences Building, Seattle, WA, 98195, USA.
authors.forename: David
authors.initials: D
authors.lastname: Benkeser
authors.affiliation: Department of Epidemiology and Evaluation, IMIM (Hospital del Mar Medical Research Institute), Pg Marítim 25-29, 08003, Barcelona, Spain.|Research Network on Health Services in Chronic Diseases (REDISSEC), Madrid, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Sala
authors.affiliation: Department of Epidemiology and Evaluation, IMIM (Hospital del Mar Medical Research Institute), Pg Marítim 25-29, 08003, Barcelona, Spain. xcastells@hospitaldelmar.cat.|Research Network on Health Services in Chronic Diseases (REDISSEC), Madrid, Spain. xcastells@hospitaldelmar.cat.
authors.forename: Xavier
authors.initials: X
authors.lastname: Castells
mesh_terms: D000368:Aged; D001940:Breast / Q000000981:diagnostic imaging*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008327:Mammography / Q000379:methods*; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009017:Morbidity / Q000639:trends; D009664:Norway / Q000453:epidemiology; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013030:Spain / Q000453:epidemiology; D014481:United States / Q000453:epidemiology
keywords: Mammographic screening; Positive predictive value; Sensitivity; Specificity; Variability