Association of State Dense Breast Notification Laws With Supplemental Testing and Cancer Detection After Screening Mammography

Objectives. To evaluate the association of state dense breast notification (DBN) laws with use of supplemental tests and cancer diagnosis after screening mammography. Methods. We examined screening mammograms (n =1 441 544) performed in 2014 and 2015 among privately insured women aged 40 to 59 years living in 9 US states that enacted DBN laws in 2014 to 2015 and 25 US states with no DBN law in effect. DBN status at screening mammography was categorized as no DBN, generic DBN, and DBN that mandates notification of possible benefits of supplemental screening (DBN+SS). We used logistic regression to examine the change in rate of supplemental ultrasound, magnetic resonance imaging, breast biopsy, and breast cancer detection. Results. DBN+SS laws were associated with 10.5 more ultrasounds per 1000 mammograms (95% CI = 3.0, 17.6 per 1000; P= .006) and 0.37 more breast cancers detected per 1000 mammograms (95% CI = 0.05, 0.69 per 1000; P=.02) compared with no DBN law. No significant differences were found for generic DBN laws in either ultrasound or cancer detection. Conclusions. DBN legislation is associated with increased use of ultrasound and cancer detection after implementation only when notification of the possible benefits of supplemental screening is required.