Supplemental Breast Imaging Utilization After Breast Density Legislation in North Carolina

Breast density notification laws are increasingly common but little is known of how they affect supplemental screening use. The aim of this study was to investigate supplemental screening before and after density notification in North Carolina, where notification has been required since 2014.

Breast screening data from Carolina Mammography Registry participants aged 40 to 79 years with no personal histories of breast cancer or breast implants were evaluated. Supplemental screening was defined as a nondiagnostic digital breast tomosynthesis (DBT), whole-breast ultrasound, or breast MRI performed within 3 months of negative or benign results on screening mammography (2-D or DBT). Supplemental screening before (2012-2013) and after (2014-2016) the notification law was compared using logistic regression.

During the study period, 78,967 women underwent 145,279 index screening mammographic examinations. Supplemental screening use was similar before and after the notification law, regardless of breast density (dense breasts: adjusted odds ratio [aOR], 1.01; 95% confidence interval [CI], 0.58-1.75; nondense breasts: aOR, 0.63; 95% CI, 0.38-1.04). Although there was no change in supplemental screening, new use of any screening DBT from 2014 to 2016 was greater for women with dense breasts (versus nondense breasts; aOR, 1.15; 95% CI, 1.08-1.23).

Data suggest that supplemental screening use in North Carolina did not change after enactment of a breast density notification law, though the increase in new use of any screening DBT was greater for women with dense breasts. The short-term lack of change in supplemental screening should be considered as additional notification laws are developed.