Do Dense Breast Laws Increase Use of Supplemental Screening?
Background
Screening mammography remains the cornerstone of breast cancer screening, but cancers are often masked in women with dense breasts, increasing the risk of interval cancers and delaying diagnosis. Dense breasts also increase the risk of developing breast cancer (see how breast density compares to other risk factors). Because of these challenges, supplemental screening breast MRI is recommended [or ultrasound (US) if MRI is not an option] for women with extremely dense breasts, women with heterogeneously dense breasts who have other risk factors, and for high-risk women with any breast density.
To improve patient awareness and access to supplemental screening, many U.S. states have enacted dense breast legislation. These laws typically fall into two categories: inform (also called “notification”), or insurance coverage. Inform mandates require radiologists to include information about breast density in the mammogram results letter, with a national standard mandated by the FDA as of 9/10/2024. Insurance mandates require insurers to cover supplemental screening (though coinsurance and deductibles often apply and there are many exemptions), with a patchwork of state laws. Federal HRSA guidelines effective 1/1/2026 have set a federal standard for expanded insurance coverage for most private plans, but Medicare, Tricare, and VHA are exempt, and Medicaid coverage varies. The Find It Early Act would address gaps in coverage, and reaching out to senators and representatives in support of this act is important.
Recent Study
In this retrospective quasi-experimental cohort study using the USA national MarketScan Commercial Claims and Encounter Database from 2008 through 2019, researchers evaluated which legislative frameworks and specific messaging features were most effective at driving the clinical uptake of supplemental imaging. The study included 12,555,082 commercially insured women aged 40–64 years who underwent screening mammography and maintained continuous insurance coverage for at least six months afterward. Using a staggered-adoption difference-in-differences design, investigators evaluated how different state dense breast laws influenced the use of screening US and MRI.
Key Findings
- Insurance coverage mandates were the strongest legislative driver of screening US use¹.
- Dense breast inform mandates independently increased the use of both screening US and MRI².
- Inform laws that explicitly mentioned the potential benefit of supplemental screening were associated with substantially greater US utilization³.
- Targeted notifications directed specifically to women with dense breasts were more effective than universal notifications at increasing use of supplemental screening⁴.
- Despite these legislative changes, the overall use of supplemental screening remained low across the study population⁵.
The findings suggest that insurance coverage is the most important factor in translating patient awareness into clinical action. While inform laws increased awareness, insurance mandates had a much greater impact on supplemental US use (13 vs. 47 additional examinations per 1,000 women), highlighting the importance of reducing financial barriers. Laws that notified only women with dense breasts and included information about supplemental screening were more effective than universal notification of all women. Although insurance coverage increased screening US use, MRI utilization remained low, suggesting that factors beyond insurance, such as access, availability, referral patterns, and patient preference, continue to limit its use.
Limitations
Claims data could not reliably distinguish screening from diagnostic imaging, which may have overestimated supplemental screening rates. The study included only commercially insured women, and do not generalize to Medicare, VHA, Tricare, Medicaid, or uninsured populations. Claims data lacked patient level characteristics, including breast density: uptake rates were determined across all women and are expected to be substantially higher in women with dense breasts. The authors did not distinguish state laws that require informing all woman of their specific density category (e.g. PA) vs. those that sent general information to all women about breast density (e.g. CT). These data preceded the 2024 national FDA standard. Further studies integrating claims data with cancer registries and electronic health records are needed to determine whether current legislative changes ultimately improve breast cancer outcomes.
Detailed Results
¹ Insurance coverage mandates increased supplemental US use by an absolute 4.7 percentage points (47 additional examinations per 1,000 women) and this represented significantly higher odds of US utilization (OR, 1.88; 95% CI, 1.86–1.90). MRI insurance coverage was not associated with increased MRI use (OR, 1.01; 95% CI, 0.96–1.05).
² Notification mandates were associated with modest but significant increases in use of screening US (OR, 1.09; 95% CI, 1.08–1.10) and breast MRI (OR, 1.09; 95% CI, 1.06–1.12). These findings corresponded to approximately 13 additional screening US examinations and 1 additional screening MRI examination per 1,000 women.
³ Notifications that included explicit language about supplemental screening tests were associated with substantially greater US use (OR, 2.84; 95% CI, 2.81–2.86).
⁴ Targeted notifications (sent only to women with dense breasts) were associated with higher odds of use of screening US (OR, 1.32; 95% CI, 1.31–1.33) and breast MRI (OR, 1.23; 95% CI, 1.19–1.27) compared with universal notification laws.
⁵ Across the entire study population of 12,555,082 women, only 9.0% underwent supplemental US and 0.6% underwent breast MRI within six months of screening mammography, demonstrating that overall supplemental screening remained relatively uncommon despite legislative changes. The study could not detail results by patient breast density or risk factors and was conducted at the state population level. The authors did report that 0.5% of the population had a personal history of breast cancer.