Breast density notification laws: Greater utilization of supplementary tests could affect millions of women

Nurse giving mammogram exam to standing patient

A diagnosis of breast cancer is devastating news, but the shock is infinitely worse if a woman discovers—often much later—that she has cancer despite receiving a clean mammogram. Unfortunately, this scenario can happen if a woman has dense breasts containing a higher proportion of fibrous tissue than fat, which are known to decrease a mammogram’s ability to detect breast cancer. To educate women of this limitation, states have enacted laws that require women with dense breasts to be notified after a mammogram, so that they can choose to undergo supplementary tests to improve cancer detection.

In a new study published this week in the Journal of General Internal Medicine, Loren Saulsberry, PhD, a Provost’s Postdoctoral Fellow and instructor in the Department of Public Health Sciences the University of Chicago, examined the impacts of these laws to see how the provision of information on women’s breast densities influences the utilization of these supplementary tests across states. She found that while the utilization of supplementary tests increased modestly, this trend may not always equate to better outcomes.

The road to optimal healthcare is paved with good intentions

In February 2019, Congress passed a national breast density notification law. Prior to that, 38 states and the District of Columbia separately enacted such laws, but they varied widely across states in how information about breast density was communicated. Furthermore, the typical supplementary tests for women with dense breasts, such as breast imaging and biopsies, have been shown to rarely make new cancer diagnoses. As such, understanding of how women respond to notifications of high breast density is important to evaluate how these laws may influence the quality of patient care.

Saulsberry’s study analyzes the claims data of women with private insurance to determine the use of supplemental breast imaging and biopsies. She examined trends in the utilization of these supplementary tests in twelve states with breast density notification laws before and after the laws were passed.

The research showed that while both states with and without notification laws saw an increase in supplementary imaging and biopsies over time, the increase was larger in the states with such laws. The differences in the increases in breast imaging and biopsies were as large as 3.3% and 0.8%, respectively, 18 months after the laws went to effect, compared to neighboring states without such laws. In states where the laws mandated insurance coverage for the supplementary tests, such as Connecticut, the increases were even greater.

Although the increases might seem modest, these results translate to a significant number of women undergoing follow-up tests each year. Approximately 43% of women between ages 40 and 74 have dense breasts, and about 40 million women receive mammograms every year. Therefore, with modest increases, “You could be talking about millions of women who opt in and make their decision with their doctor to have these supplemental imaging procedures or a breast biopsy,” Saulsberry said.

Breast density notification laws: The road travelled too hastily?

Increased rates of follow-up tests translate to higher costs to the patient and insurance providers because supplementary tests and biopsies are typically more expensive than a mammogram. Furthermore, evidence shows that such supplemental imaging tests are associated with false positives, unnecessary biopsies, and possible overdiagnosis. Breast ultrasound, the most popular option, only makes an additional 4.4 cancer detections out of 1000.

Given the higher costs and the lack of evidence on the health benefits of these supplemental tests for women with dense breasts, the assumption that breast density notification laws will improve cancer outcomes is a tenuous one. Currently, there is no solid evidence for the value of supplementary tests and biopsies for women with dense breasts. Nevertheless, Saulsberry’s study indicates that breast density notification laws may have substantial effects on patient care.

“All of us— policy makers, clinicians, researchers alike—should be mindful of some of these downstream effects and potential costs, as well as the benefits and harms of unnecessary procedures,” Saulsberry said. “We need to conduct additional research, constantly monitor what the effects are on the costs and patient outcomes and adjust accordingly to the context for what best serves not only the patients but also their healthcare providers.”