Slanetz, P.J., et al.
http://www.nejm.org/doi/full/10.1056/NEJMp1413728?af=R&rss=currentIssue
Ever since Nancy Cappello, a Connecticut woman who hadn't been told that her mammograms showed dense breast tissue, was diagnosed with stage 3 breast cancer in 2004 and advocated for a new state law, there's been a growing movement to educate women about breast density and the potential role of supplemental screening in early cancer detection. Cappello's state was the first to pass a law requiring physicians to offer supplemental whole-breast ultrasonography to women with dense breasts — defined as containing more than 50% fibroglandular tissue — and mandating that insurers cover the additional screening.
Since then, the number of breast-density laws in the United States has grown rapidly: as of January 2015, a total of 21 states had adopted such legislation. Laws vary considerably among states, with some requiring only that physicians notify women with dense breasts of their status and others stipulating that supplemental screening be offered to such women. Most state laws, however, do not mandate insurance coverage of additional screening, though the lack of such coverage could increase income-based health disparities.
