Insurance mandates, not just notifications, drive supplemental breast screening

For millions of American women, a routine mammogram comes with an unexpected complication: the discovery that dense breast tissue may be masking what the X-ray cannot show. Dense breasts are not a rare occurrence. According to the National Cancer Institute, more than 40 percent of American women aged 40 and older have dense breast tissue, a condition that both makes cancer harder to detect on mammograms and independently raises the risk of developing breast cancer in the first place. The double burden has prompted lawmakers across the United States to pass two distinct types of legislation aimed at closing the screening gap, and a new nationwide analysis now offers the clearest picture yet of which of those laws actually moves the needle.

The study, published in JAMA Network Open by researchers at Penn State College of Medicine, examined the de-identified health records of 12.6 million American women between the ages of 40 and 64 who received routine mammograms between 2008 and 2019. The team, led by first author Dong-Won Kang of Ajou University in Korea and senior author Chan Shen, Howard E. Morgan Professor in Surgery and professor of public health sciences at Penn State College of Medicine, set out to disentangle the effects of two legislative approaches that prior research had often bundled together. The first approach, notification laws, requires mammography facilities to tell women when a radiologist identifies dense breast tissue on their scan. The second, insurance coverage mandates, requires health insurers to pay for supplemental follow-up tests such as breast ultrasound and magnetic resonance imaging.

The central finding is striking in its asymmetry. Both forms of legislation independently produced modest increases in supplemental imaging, but insurance coverage mandates had nearly four times the impact of notification laws alone. When states required insurers to cover the cost of supplemental ultrasound, use of the procedure rose by roughly 47 additional examinations per 1,000 women screened. Notification laws, by comparison, were associated with about 13 additional ultrasounds per 1,000 women. In other words, telling a woman she has dense breasts opens a door, but paying for what lies beyond that door is what gets most patients through it.

Understanding why this distinction matters requires a brief look at the biology of breast density. Breasts are composed of three tissue types: fibrous connective tissue, glandular tissue and fatty tissue. Women with dense breasts carry proportionally more fibrous and glandular tissue, which appears white on a mammogram. Tumors and other abnormal changes also appear white, which means dense tissue can effectively camouflage malignancies against a bright background, a phenomenon radiologists describe as masking. Compounding the problem, dense tissue cannot be felt during a physical examination and can only be identified through medical imaging, which is precisely why so many women remain unaware of their own density status without legislative intervention.

The legislative landscape that has emerged is far from uniform, and that variation became a key analytical lever for the Penn State team. As Shen explained, some states require notifications to be sent only to women with dense breasts, while others send a general notice to everyone undergoing mammography. Some states include information about supplemental screening options in their notification letters, and others do not. A smaller number of states have gone further with insurance mandates, some covering ultrasound only, some covering MRI only, and some covering both. Pennsylvania offers a concrete example of the progression: the state passed its Breast Density Notification Act in 2013, requiring facilities to inform patients of density findings, and beginning in 2022 it required all health insurers to cover breast ultrasounds and MRIs for women with high-risk conditions, including dense breast tissue. At the federal level, the Food and Drug Administration began requiring mammography facilities to inform all patients about their breast density in 2024, but no federal law mandates coverage for supplemental testing.

Working within the MarketScan national insurance claims database, the researchers analyzed records from women who had continuous insurance coverage for at least six months after their screening mammogram. The population distribution across legislative environments revealed how uneven adoption has been: 21 percent of women in the sample lived in states with dense breast notification laws, and nearly 60 percent of those lived in states whose notifications included information about supplemental screening. Only 7 percent lived in states requiring insurance coverage for ultrasounds, and just 3 percent lived in states requiring MRI coverage. This patchwork allowed the investigators to compare outcomes across policy regimes while controlling for the confounding that had limited earlier studies.

The granularity of the findings extended beyond the headline contrast. Within states that had notification laws, ultrasound uptake was higher when the laws required notices to mention supplemental screening explicitly, and when notices were targeted specifically to women with dense breasts rather than sent to all screening patients. Notification laws were also associated with a small increase in MRI use, on the order of one additional examination per 1,000 women screened. Insurance mandates for MRI, however, produced no statistically significant change in MRI utilization, a result Shen attributed to the fact that patients with a personal or family history of breast cancer were already much more likely to receive MRI imaging, making this modality less responsive to legislative nudges. She also pointed to cost and logistics that the study did not measure directly: MRIs are generally more expensive tests, and there are fewer facilities offering them, which may create accessibility barriers that dampen demand regardless of what insurers are required to pay.

Perhaps the most sobering statistic in the study concerns the overall baseline. Across the entire sample, only 9 percent of women received supplemental ultrasound imaging and a mere 0.6 percent received supplemental MRI within six months of a screening mammogram, despite the fact that more than 40 percent of middle-age and older women have dense breasts. Even in the most supportive policy environments, supplemental imaging remains the exception rather than the rule. The analysis also identified demographic gradients in follow-up care: older women, women living in rural communities, and those with other health conditions were all less likely to obtain supplemental screening, suggesting that geography, comorbidity and age compound the financial barriers that insurance mandates are designed to remove.

Shen was careful to frame the results without overstatement. Not everyone with dense breasts needs supplemental screening, she noted, but a woman first needs to know whether she has dense breasts before she can make that decision in consultation with her healthcare provider. The findings, she argued, point to logistical and geographical barriers that influence whether women pursue follow-up screening, including cost, the availability of imaging facilities and patient preference. While more research is needed, the study offers a roadmap for policymakers seeking to maximize the public health impact of dense breast legislation: notification requirements raise awareness, but coverage requirements convert awareness into action, and the two work best in combination with attention to the practical obstacles that keep rural and older patients away from imaging centers.

For a field in which supplemental screening policy is still being written state by state, the study provides the first large nationwide evidence that the design details of legislation matter enormously. A notification letter that mentions supplemental screening reaches more women than a generic notice, and an insurance mandate reaches roughly four times as many as any letter alone. With the FDA’s federal notification requirement now in effect but coverage decisions left to states and insurers, the Penn State analysis suggests that the next frontier in dense breast policy is not information but access, ensuring that the women who learn about their density can actually afford and reach the tests that might catch what a mammogram missed.

Subject of Research: The effect of dense breast notification laws and insurance coverage mandates on supplemental breast imaging use after mammography

Article Title: Breast density laws linked to higher ultrasound use after mammography

Article References: Breast density laws linked to higher ultrasound use after mammography. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: breast density, mammography, supplemental screening, breast ultrasound, breast MRI, insurance mandates, notification laws, breast cancer screening, health policy, JAMA Network Open, Penn State College of Medicine, screening disparities