The importance of enabling informed decision making for women considering breast cancer screening

Sasieni et al. ¹ have commented on our Lancet report of a randomised controlled trial of a breast screening decision aid. ² We disagree with the authors on several points.

While the majority of women who received the intervention decision aid found it to be either completely balanced (43%) or slanted towards screening (21%), some considered it a little (30%) or clearly (6%) slanted away from screening. Women’s attitudes to breast screening tend to be strongly favourable, having been shaped by decades of promotional campaigns designed to persuade them of the benefits of screening, without explaining the risk of overdetection. Because women are accustomed to receiving positive messages about screening that strongly endorse participation, it is not surprising that some perceived the decision aid, which aimed to present a more balanced and complete picture, as slanted away from screening. As a participant in our decision aid piloting interviews explained:

It’s totally different to the traditional information (‘get screened, be safe, do all these tests’) … People aren’t used to being given information to make a balanced choice. We are used to being given ‘go and do this, it’s good for you’ … Being given the facts, we don’t get treated like that very often.” ³

It remains challenging to provide information that is both objectively balanced and perceived as balanced by the relevant audience.

Sasieni et al. are worried that 16% of women in the intervention group reported being unsure regarding their breast screening intentions at the initial follow-up several weeks post-intervention. ¹ Yet being unsure about whether to screen indicates a thoughtful, realistic, and rational response to a ‘close call’, that is, a choice with finely balanced benefits and harms. ⁴ Being unsure does not imply that these women were uninformed. The level of knowledge in those women who were unsure was just as good as that in the majority who intended to be screened.

Finally, it is widely acknowledged that, in a modern healthcare system, women must be given the opportunity to make an informed choice about whether to undergo breast screening, supported by balanced, objective information.^5–10 Alerting women to the risk of harm through overdetection is an ethical responsibility. The importance of this is arguably even greater due to the fact that screening involves offering an intervention to people who are well, as opposed to providing symptomatic patients with medical help they have sought.