Breast density reporting laws gain popularity, but are they effective?

Breast density reporting laws now exist in 24 states, but according to a recent opinion piece in JAMA Internal Medicine, there is little evidence that those laws are effective.

The commentary was written by Jennifer S. Haas, MD, division of general internal medicine and primary care at Brigham and Women’s Hospital in Boston, and Celia P. Kaplan, division of general internal medicine and department of medicine at the University of California, San Francisco. They wrote that the breast density reporting laws first began with the best of intentions, but don’t appear to be beneficial to patients.

“Breast density notification laws are unlikely to improve our understanding of breast cancer risk, screening, and diagnosis or to save lives,” the authors wrote. “Instead, the laws may result in substantial personal harms and societal costs.”

Haas and Kaplan pointed to statistics that show these laws give women the false impression that additional testing is better for them. In addition, they cited statistics that show the minimal effect dense breasts actually have on a patient’s risk of cancer.  

“The absolute 5-year risk of breast cancer for a 45-year-old woman with average breast density, no family history of breast cancer, and no history of prior breast biopsy is 0.7% and that of a similar woman with extremely dense breast tissue is 1.3%,” the authors wrote.

Another one of the authors’ problems with the laws is that they put added pressure on radiologists, and that pressure could lead to inaccurate findings.

“Interpretation of breast density is subjective,” the authors wrote. “Wary of the additional complexity introduced by breast density legislation, radiologists may downgrade their assessment of density to avoid requirements for reporting, or they may upgrade their reporting so that supplemental screening can be ordered to minimize liability, thus limiting the validity of a breast density assessment.”

There’s added pressure on patients as well, in the form of what Haas and Kaplan call “the morbidity of unneeded treatment.” This includes an increase in the likelihood of unfortunate situations such as unnecessary biopsies and false-positive results.

The authors explained that the medical landscape is much different than when the laws first started being considered. New studies related to breast cancer and breast cancer screenings are being conducted all the time, and technology is rapidly improving.

“A legislated approach to medical care is cumbersome as new evidence becomes available,” the authors wrote. “Digital mammography and digital breast tomosynthesis ... are being broadly disseminated into clinical practice. Both technologies may be superior to the film mammography that was commonly used a decade ago, when the advocacy began for breast density notification laws.”

Haas and Kaplan also fear that the continued focus on breast density may take away from other health factors, such as heart disease, which is the No. 1 cause of death for women.

In their commentary, the authors brought up the U.S. Preventive Services Task Force (USPSTF), which sparked controversy back in April when it gave biennial mammograms for women ages 50 to 74 the all-important “B” grade, but not mammograms for women ages 40 to 49 or annual mammograms for women of any age.

Many politicians and organizations came out against the USPSTF recommendations, but Haas and Kaplan suggest they make much more sense than these breast density reporting laws.

In a follow-up conversation with, Haas touched on why these recommendation make the most sense.  

“USPSTF recommendations are based on the current evidence,” Haas said via email. “Unfortunately, evidence accrues slowly. I think that is the reason that politicians and advocates have tried to use legislation to bypass this. But the unfortunate reality is that care that isn’t evidence-based may result in unintended adverse consequences (overdiagnosis, overuse of tests) that can have a negative impact both for individuals and society.”