By Rebecca E. Smith

The U.S. Food and Drug Administration (FDA) proposed updates to the Mammography Quality Standards Act (MQSA) of 1992 that will require radiology facilities to provide breast density notifications to women. Dense breast tissue makes it difficult to see cancers on a mammogram and dense breasts also put women at higher risk for breast cancer. Notification aims to provide women information to support conversations with their healthcare providers about their personal breast cancer risk and screening options. However, there is not clear clinical guidance on when and with whom to discuss imaging that is supplemental to mammography, because evidence is still evolving about the benefits of supplemental imaging, given various cancer risk scenarios; and breast cancer screening guidelines differ in recommendations for women with dense breasts. For example, the American College of Radiology recommends magnetic resonance imaging (MRI) in addition to mammography for women with dense breasts while the U.S. Preventive Services Task Force states there is insufficient evidence to recommend MR or other supplemental screening for women with dense breasts whose screening mammogram was negative.

While we await release of the detailed MQSA updated rule, existing state density reporting laws and policies remain in place. Understanding the effectiveness of existing policies for informing women of their breast density, and their impact on cancer worry and future screening intentions is informative in both the development of federal notification language and support tools for clinicians who will need to engage patients in conversations about breast density and cancer risk.

In 2009, Connecticut was the first state to pass breast density notification legislation. Currently 40 states have implemented some form of legislation or policy focused on density education with some set to expire in less than 1 year. There is no standard legislated content between states. For example, some states require only general information be given about breast density but do not require a woman to be informed of her personal density. Other states include language to encourage women with dense breasts to engage in further conversation with their providers about their personal cancer risk and screening options. While some states require density information be sent to all women (with both dense and non-dense breasts), and some send information to only those with dense breasts.


Research, including our own, suggests that awareness of breast density has increased over the past decade but there is room for improvement. In a study we conducted of 1,528 women from 8 mammography facilities in states with varying density notification laws we found that the majority (76%) of women correctly thought they had dense breasts while only 14% of women correctly knew they had non-dense breasts. Interestingly, 34% of women with non-dense breasts thought they had dense breasts. It’s not clear why women tend to frequently think they have dense breasts and if increasing density awareness contributes to that. Breast density may change over a woman’s lifetime, typically resulting in a reduction in density after menopause, which may result in different density notifications or none at all. While state policies are in place a woman who moves from one state to another may encounter entirely different language about her breast density if a notification is sent. Further, Sprague et al. found the chance of a woman being told she has dense or non-dense breasts varies widely by which radiologist interprets her mammogram. It is easy to see why women may be confused about their density and why clinician engagement in discussions on the topic are vital.

We also found that women with non-dense breasts who lived in states that sent notifications to both those with dense and non-dense breasts were significantly more likely to know their breast density. While this is not surprising, there may be quality of life benefits to density education for all women, such as reduced worry about cancer. We found that women who thought they had non-dense breasts had less worry about screening and less desire for additional screening.

Supplemental screening has potential benefits of detecting cancer not seen on a mammogram and reducing worry, but also has potential for harms. These include unnecessary callbacks (further diagnostic work-up in the absence of a cancer diagnosis), and overdiagnosis (diagnosing a cancer that will not cause symptoms or death during a woman's lifetime), which are difficult concepts to convey in written notifications in a manner that is tailored to a wide range of reading levels. The balance of benefits and harms may be better expressed by clinicians in one-on-one conversations with their patients and with clinical decision support tools. In our study, we found that lower education level was associated with a significantly lower chance of a woman knowing her breast density. This suggests that density notification has the potential to increase disparities in breast cancer screening if notifications are not designed with lower reading levels in mind and if clinicians do not engage in personalized conversations about breast density with their patients. Clinical decision support tools will also need tailoring to meet the needs of multiple socio-demographic groups.


Consideration should not only be given to how a woman weighs the trade-off between a false positive (resulting in an unnecessary callback) and detecting cancer, but also to the costs of screening. Insurance coverage for supplemental screening varies by level of medical necessity and insurance carrier, resulting in it not always being covered by a woman’s insurance. The cost of care is another known driver of health disparities in the U.S. Women should not learn of this variation in insurance coverage through the form of a surprise bill only after imaging is performed.

Women of lower socio-economic status may not have as many resources to engage in decision-making with their clinicians or to pay for supplemental imaging. It is well documented that rural patients have a higher burden to accessing care (cost and time) than their urban counterparts, and black women have a higher breast cancer mortality rate than white women. Careful attention is needed to ensure that breast density notifications have their intended beneficial effect and do not create further disparities in care.

Addressing how clinics effectively incorporate breast density conversations into routine clinical care is an area that needs more research, but imbedding reminders and decision support tools in electronic medical records (EMRs) can prompt needed conversations at the point of care and has been shown to improve patient outcomes. Including these conversations in routine care will help to ensure that women understand notifications and what their density means about their personal risk of breast cancer. Discussions about cancer risk should not only include breast density but also other risk factors such as age and family history. A study by Kerlikowske et al. showed that identifying women for supplemental screening by considering both breast density and breast cancer risk is better at optimizing the balance of benefits and harms than when only breast density is considered. One of multiple tools available for assessing breast cancer risk is the Breast Cancer Surveillance Consortium (BCSC) 5-year risk calculator, which has been externally validated in the Mayo Mammography Health Study. Unless such tools are embedded into EMR systems, clinicians must have knowledge of which tools to use and take initiative to access them online or through external applications.

Sending women notifications about their breast density is a good first step toward reaching one of the FDA’s specified aims for the new MQSA rule of “improv[ing] the delivery of mammography services by strengthening the communication of healthcare information; [and] allowing for more informed decision-making by patients and providers.” But notifications alone do not appear to reach this goal for all women. Our recent research on women’s knowledge of breast density suggests that some women are misunderstanding information about their density or are not having conversations with their providers about its implications. Clinicians need tools guided by evolving evidence to effectively engage in conversations with women about breast density, breast cancer risk, and supplemental screening. With national breast density legislation pending, the time is now to implement tools in routine clinical care to ensure density notification results in the intended positive outcomes.

About the author: Rebecca E. Smith is a Ph.D. student in the Dartmouth Institute for Health Policy and Clinical Practice’s doctoral program and a research project manager at Dartmouth Hitchcock Medical Center. Previously, for a combined 10 years, she was a research fellow and project manager in the Dartmouth Institute for Health Policy & Clinical Practice, Geisel School of Medicine at Dartmouth.