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The effect of information about overdetection of breast cancer on women's decision-making about mammography screening: study protocol for a randomised controlled trial
  1. Jolyn Hersch1,
  2. Alexandra Barratt2,
  3. Jesse Jansen1,
  4. Nehmat Houssami3,
  5. Les Irwig3,
  6. Gemma Jacklyn4,
  7. Haryana Dhillon5,
  8. Hazel Thornton6,
  9. Kevin McGeechan2,
  10. Kirsten Howard3,
  11. Kirsten McCaffery1
  1. 1Screening & Test Evaluation Program (STEP) and Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), School of Public Health, University of Sydney, Sydney, Australia
  2. 2Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), School of Public Health, University of Sydney, Sydney, Australia
  3. 3Screening & Test Evaluation Program (STEP), School of Public Health, University of Sydney, Sydney, Australia
  4. 4School of Public Health, University of Sydney, Sydney, Australia
  5. 5Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), Central Clinical School, University of Sydney, Sydney, Australia
  6. 6Department of Health Sciences, University of Leicester, Leicester, UK
  1. Correspondence to Associate Professor Kirsten McCaffery; kirsten.mccaffery{at}


Introduction Women are largely unaware that mammography screening can cause overdetection of inconsequential disease, leading to overdiagnosis and overtreatment of breast cancer. Evidence is lacking about how information on overdetection affects women's breast screening decisions and experiences. This study investigates the consequences of providing information about overdetection of breast cancer to women approaching the age of invitation to mammography screening.

Methods and analysis This is a randomised controlled trial with an embedded longitudinal qualitative substudy. Participants are a community sample of women aged 48–50 in New South Wales, Australia, recruited in 2014. Women are randomly allocated to either quantitative only follow-up (n=904) or additional qualitative follow-up (n=66). Women in each stream are then randomised to receive either the intervention (evidence-based information booklet including overdetection, breast cancer mortality reduction and false positives) or a control information booklet (including mortality reduction and false positives only). The primary outcome is informed choice about breast screening (adequate knowledge, and consistency between attitudes and intentions) assessed via telephone interview at 2 weeks postintervention. Secondary outcomes measured at this time include decision process (decisional conflict and confidence) and psychosocial outcomes (anticipated regret, anxiety, breast cancer worry and perceived risk). Women are further followed up at 6 months, 1 and 2 years to assess self-reported screening behaviour and long-term psychosocial outcomes (decision regret, quality of life). Participants in the qualitative stream undergo additional in-depth interviews at each time point to explore the views and experiences of women who do and do not choose to have screening.

Ethics and dissemination The study has ethical approval, and results will be published in peer-reviewed journals. This research will help ensure that information about overdetection may be communicated clearly and effectively, using an evidence-based approach, to women considering breast cancer screening.

Trial registration number Australian New Zealand Clinical Trials Registry ACTRN12613001035718.

  • breast neoplasms ,mammography screening
  • decision making
  • informed choice

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