Breast density notification laws: Do biopsies and other supplementary tests lead to better outcomes?

A diagnosis of breast cancer is devastating news, but the shock is infinitely worse if you discover — often much later — that you have cancer despite receiving a clean mammogram.

Unfortunately, this scenario can happen if you have dense breasts containing a higher proportion of fibrous tissue than fat, which is known to decrease a mammogram’s ability to detect breast cancer.

In recent years, 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 study published in the Journal of General Internal Medicine, Loren Saulsberry, PhD, Assistant Professor in the University of Chicago’s Department of Public Health Sciences, examined the impacts of these laws to see how information on breast density influences the utilization of these supplementary tests across states.

Saulsberry found that while the use of supplementary tests increased modestly, it didn’t 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 patients with dense breasts, such as breast imaging and biopsies, have been shown to rarely make new cancer diagnoses. As such, an understanding of how people respond to notifications of high breast density is important to evaluate how these laws may influence the quality of patient care.

Saulsberry’s study analyzed the claims data of patients with private insurance to determine the use of supplemental breast imaging and biopsies. She examined trends in the utilization of these supplementary tests in 12 states with breast density notification laws before and after the laws were passed.

The research showed that while 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 Connecticut, where the law mandated insurance coverage for the supplementary tests, the increases were even greater.

Although the increases might seem modest, these results translate to a significant number of patients 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 traveled too hastily?

Mandated insurance coverage for supplemental screenings can have both benefits and risks. More tests mean higher costs to the patients and insurance providers, as supplementary tests such as biopsies are more expensive than mammograms.

Furthermore, evidence shows that 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 1,000.

Given the higher costs and the lack of evidence on the health benefits of these supplemental tests for people 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 people 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.”