Australian women's intentions and psychological outcomes related to breast density information

Evidence is required on whether the benefits of notifying women about breast density outweigh the potential harms to inform current and future mammogram screening practice. This study aimed to assess the effect of breast density information provision on women’s intention to seek supplemental screening and psychological outcomes. We conducted a three-arm online randomised experiment with Australian women aged 40-74 years with no prior history of breast malignancy, residing in jurisdictions without existing population-based breast density notification. Women were randomised to receive one of three hypothetical breast screening result letters: screening mammogram result letter without breast density messaging (control); screening mammogram result letter with breast density messaging and an existing information letter (intervention one); and screening mammogram result letter with breast density messaging and a health literacy sensitive information letter (intervention two). Primary outcomes were intention to seek supplemental screening, feeling anxious (uneasy, worried, or nervous), informed, confused, and breast cancer worry. A total of 1420 women were randomized and included in the final analysis. Compared to the control (n=480), women who received density notification via intervention one (n=470) and intervention two (n=470) reported significantly higher (p<0.001) intention to seek supplemental screening (0.8% vs 15.6% and 14.2%), feeling anxious (14.2% vs 49.4% and 48.5%), confusion (7.8% vs 24.1% and 23.6%), and worry about breast cancer (‘quite/very worried’ 6.9% vs 17.2% and 15.5%). There were no statistical differences in these outcomes between the two intervention groups. Breast density information integrated with screening mammogram results are likely to increase women’s intention to seek supplemental screening, and to potentially make women feel anxious, confused, or worried about breast cancer. These Findings: have important relevance and implications for mammogram screening services and policymakers considering whether, and how best, to implement widespread notification of breast density as part of mammography screening.