title: The method of detection of ductal carcinoma in situ has no therapeutic implications: results of a population-based cohort study.
abstract: Population screening with mammography has resulted in increased detection of ductal carcinoma in situ (DCIS). The aim of this population-based cohort study was to assess whether the method of detection should be considered when determining prognosis and treatment in women with DCIS.
  
  
  
  This study includes 7042 women aged 49-75 years, who were surgically treated for primary DCIS between 1989 and 2004 in the Netherlands. We calculated cumulative incidences of ipsilateral and contralateral invasive breast cancer and all-cause mortality among women with screen-detected, interval, or non-screening-related DCIS, and assessed the association between method of detection and these outcomes, using multivariable Cox regression analyses.
  
  
  
  Compared with non-screening-related DCIS, women with screen-detected DCIS had a lower risk of developing ipsilateral invasive breast cancer (hazard ratio (HR) = 0.75, 95% CI = 0.59-0.96), but a similar risk of contralateral invasive breast cancer (HR = 0.86, 95% CI = 0.67-1.10). The absolute difference in risk of ipsilateral invasive breast cancer was 1% at 15 years. Screen detection was associated with lower all-cause mortality (HR = 0.85, 95% CI = 0.73-0.98); when we additionally accounted for the occurrence of invasive breast cancer the magnitude of this effect remained similar (HR = 0.86, 95% CI = 0.75-1.00).
  
  
  
  Screen detection was associated with lower risk of ipsilateral invasive breast cancer and all-cause mortality. However, the absolute difference in risk of ipsilateral invasive breast cancer was very low and the lower all-cause mortality associated with screen-detected and interval DCIS might be explained by a healthy-user effect. Therefore, our findings do not justify different treatment strategies for women with screen-detected, interval, or non-screening-related DCIS.
authors.affiliation: Division of Molecular Pathology, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Plesmanlaan 121, 1066, CX, Amsterdam, The Netherlands.|Division of Psychosocial research and Epidemiology, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Plesmanlaan 121, 1066, CX, Amsterdam, The Netherlands.|Department of Surgery, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Plesmanlaan 121, 1066, CX, Amsterdam, The Netherlands.
authors.forename: Lotte E
authors.initials: LE
authors.lastname: Elshof
authors.affiliation: Division of Psychosocial research and Epidemiology, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Plesmanlaan 121, 1066, CX, Amsterdam, The Netherlands.
authors.forename: Michael
authors.initials: M
authors.lastname: Schaapveld
authors.affiliation: Department of Surgery, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Plesmanlaan 121, 1066, CX, Amsterdam, The Netherlands.
authors.forename: Emiel J
authors.initials: EJ
authors.lastname: Rutgers
authors.affiliation: Division of Molecular Pathology, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Plesmanlaan 121, 1066, CX, Amsterdam, The Netherlands.|Division of Psychosocial research and Epidemiology, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Plesmanlaan 121, 1066, CX, Amsterdam, The Netherlands.
authors.forename: Marjanka K
authors.initials: MK
authors.lastname: Schmidt
authors.affiliation: Department of Research, Netherlands Comprehensive Cancer Organisation (IKNL), Godebaldkwartier 419, 3511, DT, Utrecht, The Netherlands.
authors.forename: Linda
authors.initials: L
authors.lastname: de Munck
authors.affiliation: Division of Psychosocial research and Epidemiology, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Plesmanlaan 121, 1066, CX, Amsterdam, The Netherlands.
authors.forename: Flora E
authors.initials: FE
authors.lastname: van Leeuwen
authors.affiliation: Division of Molecular Pathology, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Plesmanlaan 121, 1066, CX, Amsterdam, The Netherlands. j.wesseling@nki.nl.|Department of Pathology, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Plesmanlaan 121, 1066, CX, Amsterdam, The Netherlands. j.wesseling@nki.nl.
authors.forename: Jelle
authors.initials: J
authors.lastname: Wesseling
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000175:diagnosis* / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D002423:Cause of Death; D000066491:Clinical Decision-Making; D015331:Cohort Studies; D055088:Early Detection of Cancer / Q000379:methods; D005260:Female; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008403:Mass Screening; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D009426:Netherlands / Q000453:epidemiology; D011159:Population Surveillance; D016016:Proportional Hazards Models; D047368:Tumor Burden
keywords: Detection; Ductal carcinoma in situ; Invasive breast cancer; Mammography; Mortality; Population-based cohort; Screening