title: Trends in detection of invasive cancer and ductal carcinoma in situ at biennial screening mammography in Spain: a retrospective cohort study.
abstract: BACKGROUND
  Breast cancer incidence has decreased in the last decade, while the incidence of ductal carcinoma in situ (DCIS) has increased substantially in the western world. The phenomenon has been attributed to the widespread adaption of screening mammography. The aim of the study was to evaluate the temporal trends in the rates of screen detected invasive cancers and DCIS, and to compare the observed trends with respect to hormone replacement therapy (HRT) use along the same study period.
  
  
  METHODS
  Retrospective cohort study of 1,564,080 women aged 45-69 years who underwent 4,705,681 screening mammograms from 1992 to 2006. Age-adjusted rates of screen detected invasive cancer, DCIS, and HRT use were calculated for first and subsequent screenings. Poisson regression was used to evaluate the existence of a change-point in trend, and to estimate the adjusted trends in screen detected invasive breast cancer and DCIS over the study period.
  
  
  RESULTS
  The rates of screen detected invasive cancer per 100.000 screened women were 394.0 at first screening, and 229.9 at subsequent screen. The rates of screen detected DCIS per 100.000 screened women were 66.8 at first screen and 43.9 at subsequent screens. No evidence of a change point in trend in the rates of DCIS and invasive cancers over the study period were found. Screen detected DCIS increased at a steady 2.5% per year (95% CI: 1.3; 3.8), while invasive cancers were stable.
  
  
  CONCLUSIONS
  Despite the observed decrease in breast cancer incidence in the population, the rates of screen detected invasive cancer remained stable during the study period. The proportion of DCIS among screen detected breast malignancies increased from 13% to 17% throughout the study period. The rates of screen detected invasive cancer and DCIS were independent of the decreasing trend in HRT use observed among screened women after 2002.
authors.affiliation: Department of Epidemiology and Evaluation, IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain ; Network for Research into Healthcare in Chronic Diseases (REDISECC), Madrid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Román
authors.affiliation: Network for Research into Healthcare in Chronic Diseases (REDISECC), Madrid, Spain ; Basic Medical Sciences Department, Biomedical Research Institut of Lleida (IRBLLEIDA)-University of Lleida, Lleida, Spain.
authors.forename: Montse
authors.initials: M
authors.lastname: Rué
authors.affiliation: Department of Epidemiology and Evaluation, IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain ; Network for Research into Healthcare in Chronic Diseases (REDISECC), Madrid, Spain ; Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Sala
authors.affiliation: Navarra Breast Cancer Screening Programme, Public Health Institute, Pamplona, Navarra, Spain.
authors.forename: Nieves
authors.initials: N
authors.lastname: Ascunce
authors.affiliation: Oficina Tècnica de Cribratge, Corporació Sanitaria Parc Taulí-Institut Universitari Parc Taulí-UAB, Sabadell, Barcelona, Spain.
authors.forename: Marisa
authors.initials: M
authors.lastname: Baré
authors.affiliation: La Rioja Breast Cancer Screening Programme, Fundacion Rioja Salud, Logroño, La Rioja, Spain.
authors.forename: Araceli
authors.initials: A
authors.lastname: Baroja
authors.affiliation: Dirección General de Programas Asistenciales, Consejería de Sanidad, Servicio Canario de Salud, Tenerife, Santa Cruz de Tenerife, Spain.
authors.forename: Mariola
authors.initials: M
authors.lastname: De la Vega
authors.affiliation: Foundation Society for Cancer Research and Prevention, Pere Virgili Health Research Institute, Reus, Tarragona, Spain.
authors.forename: Jaume
authors.initials: J
authors.lastname: Galcerán
authors.affiliation: Program & Analysis Unit, Health Office, Oviedo, Principado de Asturias, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Natal
authors.affiliation: General Directorate Public Health & Centre for Public Health Research, Valencia, Comunidad Valenciana, Spain.
authors.forename: Dolores
authors.initials: D
authors.lastname: Salas
authors.affiliation: Servicio de Promoción de la Salud y Programas Preventivos, Consejería de Sanidad, Valladolid, Castilla y León, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Sánchez-Jacob
authors.affiliation: Galician Breast Cancer Screening Programme, Public Health & Planning Directorate, Health Office, Santiago de Compostela, La Coruña, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Zubizarreta
authors.affiliation: Department of Epidemiology and Evaluation, IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain ; Network for Research into Healthcare in Chronic Diseases (REDISECC), Madrid, Spain ; Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Castells
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology; D055088:Early Detection of Cancer / Q000639:trends*; D005260:Female; D020249:Hormone Replacement Therapy / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008327:Mammography; D008403:Mass Screening / Q000706:statistics & numerical data; D008875:Middle Aged; D012189:Retrospective Studies; D013030:Spain / Q000453:epidemiology