In the absence of clear guidelines, it is difficult to make recommendations about mammography screening to women 40 to 49 years of age. For this reason, the decision to proceed with mammography in this age group is often shared by physician and patient and likely is subject to influences such as the woman's fear of breast cancer, her understanding of breast cancer, and her preconceived ideas of the risks and benefits of mammography. In this study, Lewis and colleagues sought to determine whether the way in which the information about risks and benefits was framed—negatively, positively, or neutrally—had an impact on decision-making regarding mammography among women 40 to 49 years of age.
The authors identified three key content elements of mammography counseling: (1) the chance of having one's life extended by mammography, (2) the risk of false-positive test results, and (3) the effect of false-positive results on women's mental health. This information was pretested with women to assess their ability to understand its content. Eligible study participants 35 to 49 years of age were then randomized to one of three video groups.
In each video group, logically equivalent information was presented, but the information was framed differently. In the positively framed video, the mortality benefit was presented as the number of lives extended, and the false-positive information was presented as the number of women who would not experience harm. In the negatively framed video, this information was presented in terms of the number of lives not extended and the number of women harmed, while in the neutrally framed video, both aspects were presented.
Using a five-point Likert scale to determine women's perception of mammography screening before and after watching the video, the outcome measures were the change in the proportion of accurate responses to questions about the potential benefits and harms of mammography and the change in the proportion of participants who responded that the benefits of mammography were more important than the harms.
The 179 eligible participants were predominantly white, insured, and high-school graduates. On the pretest, 82 percent of women responded incorrectly to all three questions, greatly overestimating the benefit of mammography and underestimating the risk of having a false-positive result. Accuracy improved after viewing the video, but women's perceptions of the balance between harms and benefits showed little change and was not affected by framing. The relative risk of agreeing that the benefits were more important than the harms was 1.11 for the positive video compared with the negative video, 1.1 for the positive video versus the neutral video, and 1.0 for the negative video compared with the neutral video.
Although accuracy improved, women did not change their perceptions from baseline about the benefits and harms of mammography, regardless of how this information was framed. The authors speculate that factual information about mammography does not effectively counteract emotionally and psychologically rooted beliefs about breast cancer. In general, women have positive views about mammography and tend to dismiss the false-positive rate as unimportant. These beliefs, apparently unchanged despite the information provided, make it difficult to determine whether different types of framing would have an impact on decision-making in other clinical situations in which attitudes about screening might be less positive.