Invitations to screening mammography play a central part in the process of obtaining informed consent, but conflict of interest exists for publicly funded screening, since organisers want a high uptake. Research also shows that women generally exaggerate the benefits and are unaware of the harms of screening.
The researchers examined mammography invitations from English speaking and Scandinavian countries with publicly funded screening to assess whether they provide sufficient information to enable women to make an informed decision.
Thirty invitations (97%) mentioned the main benefit of screening, a reduction in breast cancer mortality, but only seven gave the size of the benefit and none of them in a helpful way. In contrast, no invitation mentioned the major harm of screening, over-diagnosis and subsequent over-treatment.
Six invitations argued that screening leads to less invasive surgery and another four stated that it leads to simpler treatment. None of the invitations noted that research has shown that screening leads to increased use of surgery and radiotherapy arising from over-diagnosis.
Fifteen invitations (48%) recommended regular breast self examinations, despite doubts over their benefit and documented harms.
Although it is good news that the invitations often included an information pamphlet, the focus on the benefits of screening is problematic, say the authors. The most important harms, over-diagnosis and over-treatment, were not mentioned and other important harms were often either omitted or downplayed.
Two-thirds (68%) of invitations gave an appointment date, but they warn that this gives the impression that participation is a public duty. They believe that information material should convey the message that a decision not to attend is not irresponsible.
"We believe that the information included with invitations should be more balanced, using absolute numbers to describe the likelihood of benefits and harms, and applying to the same time span if possible."
"Furthermore, we suggest that the responsibility for the programmes should be separated from the responsibility for the information material and that consumer groups be involved in the process of developing balanced information material," they conclude.
An editorial on the UK breast screening programme outlines recent efforts to provide women with sufficient information to make an informed choice.