title: Interval breast cancers: absolute and proportional incidence and blinded review in a community mammographic screening program.
abstract: OBJECTIVE
  To evaluate the performance of the first years since the beginning of a mammographic population-based screening program.
  
  
  METHODS
  Women aged 49-69 were invited biennially for two-view film-screen mammography and double reading without arbitration was performed. Interval cancers (ICs) from 2001 to 2006 were identified using screening archives, local pathology archives, and hospital discharge records. The proportional incidence of IC was determined considering breast cancers expected without screening. Three offsite radiologists experienced in breast cancer screening blindly evaluated mammograms prior to diagnosis, randomly mixed with negative mammograms (1:2 ratio). Cases unrecalled at review were considered as true ICs, those recalled by only one reviewer as minimal signs, and those recalled by two or three reviewers as missed cancers. T and N stage of the reviewed ICs were evaluated and compared.
  
  
  RESULTS
  A total of 86,276 first level mammograms were performed. Mean recall rate was 6.8% at first and 4.6% at repeat screening. We had 476 screen-detected cancers and 145 ICs (10 of them ductal carcinomas in situ). Absolute incidence was 17 per 10,000 screening examinations. Invasive proportional incidence was 19% (44/234) in the first year, 39% (91/234) in the second year, and 29% (135/468) in the two-year interval. Of 145 ICs, 130 (90%) were reviewed mixed with 287 negative controls: 55% (71/130) resulted to be true ICs, 24% (31/130) minimal signs, and 22% (28/130) missed cancers. The rate of ICs diagnosed in the first year interval was 21% (15/71) for true ICs, 46% (13/28) for missed cancers, and 39% (12/31) for minimal signs, with a significant difference of true ICs rate compared to missed cancers rate (p=0.012). A higher rate of T3 and T4 stages was found for missed cancers (18%, 5/28) compared to minimal signs (6%, 2/31) or true ICs (8%, 6/71), while the rate of N2 and N3 stage for both minimal signs (19%, 6/31) or missed cancers (25%, 7/28) was higher than that for true ICs (10%, 7/71), although all these differences were not significant (p ≥ 0.480).
  
  
  CONCLUSIONS
  These results showed the possibility to comply with European Community standards in the first years of a screening program implementation.
authors.affiliation: Unità di Radiologia, IRCCS Policlinico San Donato, Piazza E. Malan 2, San Donato Milanese (Mi) 20097, Italy(2). Electronic address: luca.carbonaro@gmail.com.
authors.forename: Luca A
authors.initials: LA
authors.lastname: Carbonaro
authors.affiliation: Servizio di Radiologia, Azienda Ospedaliera Circolo di Melegnano, Via Pandina 1, Vizzolo Predabissi (Mi) 20070, Italy(3).
authors.forename: Antonio
authors.initials: A
authors.lastname: Azzarone
authors.affiliation: Unità di Radiologia, IRCCS Policlinico San Donato, Piazza E. Malan 2, San Donato Milanese (Mi) 20097, Italy(2).
authors.forename: Bijan Babaei
authors.initials: BB
authors.lastname: Paskeh
authors.affiliation: Dipartimento di Radiologia, IRCCS Istituto Clinico Humanitas, Via Manzoni 56, Rozzano (Mi) 20089, Italy(4).
authors.forename: Giorgio
authors.initials: G
authors.lastname: Brambilla
authors.affiliation: Centro di Prevenzione Senologica, ULSS 20, Piazza Lambranzi, Verona 37034, Italy(5).
authors.forename: Silvia
authors.initials: S
authors.lastname: Brunelli
authors.affiliation: Servizio di Radiologia, Azienda Ospedaliera Circolo di Melegnano, Via Pandina 1, Vizzolo Predabissi (Mi) 20070, Italy(3).
authors.forename: Anna
authors.initials: A
authors.lastname: Calori
authors.affiliation: Centro di Prevenzione Senologica, ULSS 20, Piazza Lambranzi, Verona 37034, Italy(5).
authors.forename: Francesca
authors.initials: F
authors.lastname: Caumo
authors.affiliation: Dipartimento di Radiologia, IRCCS Istituto Clinico Humanitas, Via Manzoni 56, Rozzano (Mi) 20089, Italy(4).
authors.forename: Paolo
authors.initials: P
authors.lastname: Malerba
authors.affiliation: Unità di Radiologia, IRCCS Policlinico San Donato, Piazza E. Malan 2, San Donato Milanese (Mi) 20097, Italy(2).
authors.forename: Laura
authors.initials: L
authors.lastname: Menicagli
authors.affiliation: Unità di Radiologia, IRCCS Policlinico San Donato, Piazza E. Malan 2, San Donato Milanese (Mi) 20097, Italy(2); Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milano, Italy.
authors.forename: Luca M
authors.initials: LM
authors.lastname: Sconfienza
authors.affiliation: Servizio di Radiologia, Azienda Ospedaliera Circolo di Melegnano, Via Pandina 1, Vizzolo Predabissi (Mi) 20070, Italy(3).
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Vadalà
authors.affiliation: Servizio di Medicina Preventiva delle Comunità, ASL Milano 2, Via Friuli 2, Lacchiarella (Mi) 20084, Italy(6).
authors.forename: Gelma
authors.initials: G
authors.lastname: Brambilla
authors.affiliation: Servizio di Medicina Preventiva delle Comunità, ASL Milano 2, Via Friuli 2, Lacchiarella (Mi) 20084, Italy(6).
authors.forename: Luigi
authors.initials: L
authors.lastname: Fantini
authors.affiliation: Screening Program, ULSS 16, Padova, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Ciatto
authors.affiliation: Unità di Radiologia, IRCCS Policlinico San Donato, Piazza E. Malan 2, San Donato Milanese (Mi) 20097, Italy(2); Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milano, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Sardanelli
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D019058:Community Networks / Q000706:statistics & numerical data; D057210:Delayed Diagnosis / Q000706:statistics & numerical data*; D055088:Early Detection of Cancer / Q000706:statistics & numerical data*; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008327:Mammography / Q000706:statistics & numerical data*; D008875:Middle Aged; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016037:Single-Blind Method
keywords: Breast cancer; Interval cancers; Mammography; Population-based screening