How information about overdetection changes breast cancer screening decisions: a mediation analysis within a randomised controlled trial.

Content Provider	Europe PMC
Author	Hersch, Jolyn McGeechan, Kevin Barratt, Alexandra Jansen, Jesse Irwig, Les Jacklyn, Gemma Houssami, Nehmat Dhillon, Haryana McCaffery, Kirsten
Copyright Year	2017
Abstract	ObjectivesIn a randomised controlled trial, we found that informing women about overdetection changed their breast screening decisions. We now present a mediation analysis exploring the psychological pathways through which study participants who received the intervention processed information about overdetection and how this influenced their decision-making. We examined a series of potential mediators in the causal chain between exposure to overdetection information and women’s subsequently reported breast screening intentions.DesignSerial multiple mediation analysis within a randomised controlled trial.SettingNew South Wales, Australia.Participants811 women aged 48–50 years with no personal history of breast cancer.InterventionsTwo versions of a decision aid giving women information about breast cancer deaths averted and false positives from mammography screening, either with (intervention) or without (control) information on overdetection.Main outcomeIntentions to undergo breast cancer screening in the next 2–3 years.MediatorsKnowledge about overdetection, worry about breast cancer, attitudes towards breast screening and anticipated regret.ResultsThe effect of information about overdetection on women’s breast screening intentions was mediated through multiple cognitive and affective processes. In particular, the information led to substantial improvements in women’s understanding of overdetection, and it influenced—both directly and indirectly via its effect on knowledge—their attitudes towards having screening. Mediation analysis showed that the mechanisms involving knowledge and attitudes were particularly important in determining women’s intentions about screening participation.ConclusionsEven in this emotive context, new information influenced women’s decision-making by changing their understanding of possible consequences of screening and their attitudes towards undergoing it. These findings emphasise the need to provide good-quality information on screening outcomes and to communicate this information effectively, so that women can make well-informed decisions.Trial registration numberThis study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12613001035718) on 17 September 2013.
Journal	BMJ Open
Volume Number	7
PubMed Central reference number	PMC5640026
Issue Number	10
PubMed reference number	28988168
e-ISSN	20446055
DOI	10.1136/bmjopen-2017-016246
Language	English
Publisher	BMJ Publishing Group
Publisher Date	2017-10-06
Publisher Place	London
Access Restriction	Open
Rights License	This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/ © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
Subject Keyword	breast imaging overdiagnosis decision aid informed decision making cancer screening mediation
Content Type	Text
Resource Type	Article
Subject	Medicine