title: Overdetection in breast cancer screening: development and preliminary evaluation of a decision aid.
abstract: OBJECTIVE
  To develop, pilot and refine a decision aid (ahead of a randomised trial evaluation) for women around age 50 facing their initial decision about whether to undergo mammography screening.
  
  
  METHODS
  Two-stage mixed-method pilot study including qualitative interviews (n=15) and a randomised comparison using a quantitative survey (n=34).
  
  
  METHODS
  New South Wales, Australia.
  
  
  METHODS
  Women aged 43-59 years with no personal history of breast cancer.
  
  
  METHODS
  The decision aid provides evidence-based information about important outcomes of mammography screening over 20 years (breast cancer mortality reduction, overdetection and false positives) compared with no screening. The information is presented in a short booklet for women, combining text and visual formats. A control version produced for the purposes of comparison omits the overdetection-related content.
  
  
  RESULTS
  Comprehension of key decision aid content and acceptability of the materials.
  
  
  RESULTS
  Most women considered the decision aid clear and helpful and would recommend it to others. Nonetheless, the piloting process raised important issues that we tried to address in iterative revisions. Some participants found it hard to understand overdetection and why it is of concern, while there was often confusion about the distinction between overdetection and false positives. In a screening context, encountering balanced information rather than persuasion appears to be contrary to people's expectations, but women appreciated the opportunity to become better informed.
  
  
  CONCLUSIONS
  The concept of overdetection is complex and new to the public. This study highlights some key challenges for communicating about this issue. It is important to clarify that overdetection differs from false positives in terms of its more serious consequences (overtreatment and associated harms). Screening decision aids also must clearly explain their purpose of facilitating informed choice. A staged approach to development and piloting of decision aids is recommended to further improve understanding of overdetection and support informed decision-making about screening.
authors.affiliation: Screening & Test Evaluation Program (STEP) and Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), School of Public Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Jolyn
authors.initials: J
authors.lastname: Hersch
authors.affiliation: Screening & Test Evaluation Program (STEP) and Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), School of Public Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Jesse
authors.initials: J
authors.lastname: Jansen
authors.affiliation: Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), School of Public Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Barratt
authors.affiliation: Screening & Test Evaluation Program (STEP), School of Public Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Les
authors.initials: L
authors.lastname: Irwig
authors.affiliation: Screening & Test Evaluation Program (STEP), School of Public Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Nehmat
authors.initials: N
authors.lastname: Houssami
authors.affiliation: School of Public Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Gemma
authors.initials: G
authors.lastname: Jacklyn
authors.affiliation: Department of Health Sciences, University of Leicester, Leicester, UK.
authors.forename: Hazel
authors.initials: H
authors.lastname: Thornton
authors.affiliation: Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), Central Clinical School, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Haryana
authors.initials: H
authors.lastname: Dhillon
authors.affiliation: Screening & Test Evaluation Program (STEP) and Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), School of Public Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Kirsten
authors.initials: K
authors.lastname: McCaffery
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000175:diagnosis*; D003661:Decision Support Techniques; D055088:Early Detection of Cancer / Q000379:methods*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008327:Mammography / Q000523:psychology / Q000706:statistics & numerical data; D008875:Middle Aged; D010865:Pilot Projects; D036301:Qualitative Research
keywords: PREVENTIVE MEDICINE; PUBLIC HEALTH; QUALITATIVE RESEARCH