Women living in the 38 states that have enacted laws mandating that they receive information about their breast density after a mammogram do not have an increased understanding of the clinical implications of dense breasts, a study found.
Researchers conducted a nationally representative online survey among 1,928 women ages 40 to 59 years who had no personal history of breast cancer and had received at least one screening mammogram. The survey assessed reported history of increased breast density, knowledge of the increased risk of breast cancer with dense breasts, knowledge of the masking effect of dense breasts on mammography, and breast cancer anxiety. Results of the study were published by the Journal of General Internal Medicine on Jan. 8.
Women in states with dense breast notification (DBN) laws were more likely to report increased breast density than women in states without such laws (43.6% vs. 32.7%; P<0.01; adjusted odds ratio, 1.70 [95% CI, 1.34 to 2.17]). The impact of DBN on women's reporting of dense breasts was significant for women with more than a high school education but not for women with a high school education or less (P=0.01 for interaction).
Twenty-three percent of women overall knew that increased breast density was associated with a higher risk of breast cancer, and 68% of women knew that dense breasts decreased the sensitivity of mammography. No significant differences were seen in such outcomes or in breast cancer-related anxiety between women in states with DBN laws and states without them.
The proportion of women reporting breast cancer anxiety in DBN states versus non-DBN states did not differ (44.6% vs. 44.2%, respectively; P=0.87). A greater proportion of women with increased breast density reported breast cancer anxiety than did women without dense breasts (55.7% vs. 36.6%, respectively; P<0.01). However, anxiety did not differ significantly by residence in a DBN state versus a non-DBN state among women with increased breast density (54.6% vs. 61.1%, respectively; P=0.12)
The authors noted that DBN laws have been controversial and, among other limitations, acknowledged that their results may have been affected by self-reported data and causal effects. They concluded that DBN laws were associated with increased knowledge about personal breast density but not its relationship to breast cancer risk. “Ultimately, the clinical implications of a dense breast finding are complex and personalized and require a conversation between a woman and her provider,” the authors wrote. “Providers can perform a comprehensive breast cancer risk assessment needed to inform use of supplemental screening and importantly help place breast cancer risk and screening within the larger context of a [woman's] overall health priorities and goals.”