Dense breast notification laws boost cancer detection rates, ultrasound use

Dense breast notification (DBN) laws that require recommending supplemental tests and cancer diagnosis after screening mammography boosted ultrasound use and cancer detection rates in a recent study of more than 1 million women across the U.S.

In an effort to determine which DBN laws are most useful and clinically relevant, Susan Busch, a professor of public health at Yale, and co-authors examined 1.4 million screening mammograms performed among women aged 40 to 59 who lived in areas with differing legislation. While some states mandate that physicians notify their patients about breast density after a mammogram—around half of middle-aged women in the U.S. have dense breast tissue, which increases their risk of cancer and can complicate mammograms—others require those notifications to also include recommendations for supplemental screening tests like ultrasound and MRI.

The women involved in Busch et al.’s study were spread across nine states that enacted DBN laws between 2014 and 2015 and 25 states with no active DBN laws. The authors examined the change in the rate of supplemental ultrasounds, MRIs, breast biopsy and cancer detection in all patients.

The team found DBN laws that recommended supplemental testing were most effective—such laws were associated with 10.5 more ultrasounds per 1,000 mammograms and 0.37 more breast cancers detected per 1,000 mammograms compared with no DBN law.

“Notably, although we find increases, this uptake is low for an insured population with plans that cover breast ultrasounds,” Busch said in a release from Yale.

According to the study, the researchers found generic DBN laws that didn’t require additional recommendations didn’t make much of a difference in cancer detection or testing rates.

“Our study suggests that if one of the goals of dense breast notification laws is to change clinical practice, the language of the legislation is important,” Busch said. “Including specific information about additional testing is more effective than vague recommendations that suggest talking to your doctor.”

Still, Cary Gross, another author on the paper, noted that simply finding more cancers doesn’t necessarily translate to better patient care.

“Sometimes, performing more screening might simply detect more early-stage cancers that might not have caused a problem,” he said in the release. “The key outcome for a screening program is to decrease rates of advanced cancers and to decrease mortality. We need further study to determine whether these more aggressive screening strategies are actually having a positive impact.”