Optimization of an Information Leaflet to Influence Medication Beliefs in Women With Breast Cancer: A Randomized Factorial Experiment.

Adjuvant endocrine therapy (AET) is a medication given to women to stop breast cancer from returning. Many women do not take AET every day or stop taking it before they should. Some women do not take AET because they do not believe it will help them, or they have concerns about the side effects. We ran an online study aiming to create the best information leaflet to help women understand how AET is helpful and to reduce their concerns. The leaflet had five sections; diagrams explaining how AET works, visual pictures of the benefits of AET, information about the side effects, answers to common concerns, and quotes from other women with breast cancer. 1,604 healthy women filled in a questionnaire before and after looking at an information leaflet about AET. Women received different combinations of the five sections of the information leaflet. We found quotes from other women with breast cancer led to more positive beliefs about AET. Some sections of the leaflet worked better in combination, while other sections were worse in combination. Our results led us to remove the detailed side effect information from the leaflet, as in combination with the other sections this negatively affected women's beliefs about AET.