title: [Classification and characteristics of interval cancers in the Principality of Asturias's Breast Cancer Screening Program].
abstract: OBJECTIVE
  To review and classify the interval cancers found in the Principality of Asturias's Breast Cancer Screening Program (PDPCM). A secondary objective was to determine the histological characteristics, size, and stage of the interval cancers at the time of diagnosis.
  
  
  METHODS
  We included the interval cancers in the PDPCM in the period 2003-2007. Interval cancers were classified according to the breast cancer screening program protocol, with double reading without consensus, without blinding, with arbitration. Mammograms were interpreted by 10 radiologists in the PDPCM.
  
  
  RESULTS
  A total of 33.7% of the interval cancers could not be classified; of the interval cancers that could be classified, 40.67% were labeled true interval cancers, 31.4% were labeled false negatives on screening, 23.7% had minimal signs, and 4.23% were considered occult. A total of 70% of the interval cancers were diagnosed in the year of the period between screening examinations and 71.7% were diagnosed after subsequent screening. A total of 76.9% were invasive ductal carcinomas, 61.1% were stage II when detected, and 78.7% were larger than 10mm when detected.
  
  
  CONCLUSIONS
  The rate of interval cancers and the rate of false negatives in the PDPCM are higher than those recommended in the European guidelines. Interval cancers are diagnosed later than the tumors detected at screening. Studying interval cancers provides significant training for the radiologists in the PDPCM.
authors.affiliation: Servicio de Salud Poblacional, Consejería de Salud y Servicios Sanitarios del Principado de Asturias, Oviedo, Asturias, España. Electronic address: miguel.prietogarcia@asturias.org.
authors.forename: M A
authors.initials: MA
authors.lastname: Prieto García
authors.forename: R
authors.initials: R
authors.lastname: Delgado Sevillano
authors.forename: C
authors.initials: C
authors.lastname: Baldó Sierra
authors.forename: E
authors.initials: E
authors.lastname: González Díaz
authors.forename: A
authors.initials: A
authors.lastname: López Secades
authors.forename: J A
authors.initials: JA
authors.lastname: Llavona Amor
authors.forename: B
authors.initials: B
authors.lastname: Vidal Marín
mesh_terms: D001943:Breast Neoplasms / Q000145:classification* / Q000175:diagnosis* / Q000000981:diagnostic imaging; D055088:Early Detection of Cancer; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008327:Mammography; D013030:Spain