Effect of Messaging on Support for Breast Cancer Screening Cessation Among Older US Women: A Randomized Clinical Trial

Importance Many older women are screened for breast cancer beyond guideline-recommended thresholds. Messaging holds promise to reduce overscreening. Objective To investigate the effect of a message on older women's support for and intentions of stopping breast cancer screening. Design, Setting, and Participants A 2-wave randomized clinical online survey trial using a nationally representative online panel was performed from May 12 to June 19, 2023. Women 65 years or older without breast cancer were eligible to participate. Intervention A pilot-tested breast cancer screening cessation message delivered to a hypothetical older woman with serious illnesses and functional impairment. The message was described as from 1 of 3 sources (clinician, news story, or family member). Participants were randomized into 4 groups: no message (group 1 [control]), a single message from a clinician at wave 1 and no message at wave 2 (group 2), a message from a news story (wave 1) and a clinician (wave 2) (group 3), and a message from a family member (wave 1) and a clinician (wave 2) (group 4). Main Outcomes and Measures Support for stopping screening in the hypothetical older woman (primary) and screening intentions for oneself (secondary) were assessed on 7-point scales, with higher values indicating stronger support for and intentions to stop screening. Means were compared using analysis of variance. The message effect on screening intentions among participants 75 years or older and those with life expectancy of less than 10 years were also explored. Results A total of 3051 women participated in wave 1 of the trial. The mean (SD) age was 72.8 (5.9) years; 272 (8.9%) were non-Hispanic Black and 2506 (82.1%) were non-Hispanic White. Of these women, 2796 (91.6%) completed wave 2. Group 2 had significantly higher support for screening cessation in the hypothetical patient at wave 2 (mean score, 3.14 [95% CI, 2.99-3.29]) compared with group 1 (mean score, 2.68 [95% CI, 2.54-2.82]; P < .001). The effect was even stronger in group 3 (mean score, 4.23 [95% CI, 4.09-4.38]) and group 4 (mean score, 4.12 [95% CI, 3.97-4.27]) compared with both groups 1 and 2 (all P < .001). Message effects on self-screening intentions followed a similar pattern, with larger effects among participants 75 years or older or with limited life expectancy. Conclusions and Relevance In this randomized clinical trial, a breast cancer screening cessation message significantly increased older women's support for and intentions of screening cessation. The strongest effects were observed when the message was delivered over time from multiple sources. Future work needs to engage potential message sources to examine the feasibility and acceptability of multilevel messaging strategies and their effect on screening behavior.