What is Breast Density and Why is it Significant?

Breast density is classified into four types: fatty, scattered tissue, heterogeneously dense, or extremely dense. Dense breasts contain a higher proportion of fibrous and glandular tissue compared to fatty tissue. Since both fibroglandular tissue and tumors appear white on mammograms, greater breast density can complicate the detection of cancer. Approximately half of American women are categorized as having dense breasts.

It is essential to note that dense breasts are a common occurrence. However, they are also associated with an elevated risk of breast cancer, although the reasons for this correlation remain unclear. This complexity necessitates careful consideration regarding breast cancer screening. While regular mammograms are proven to save lives, additional imaging methods like ultrasound, MRI, or contrast-enhanced mammography may be beneficial for women with dense breast tissue.

The FDA's New Regulation: Key Aspects

The FDA now mandates that specific language be used to ensure all women receive clear, concise, and comprehensive information regarding breast density. After a mammogram, women must be informed about the following:

• Whether they have dense or non-dense breasts.
• The increased risk of breast cancer associated with dense breasts.
• The challenges dense breasts pose in detecting cancer on mammograms.
• The potential benefits of supplementary imaging tests for those with dense breasts.

Moreover, women are encouraged to discuss their individual circumstances with healthcare providers to determine the necessity of additional screening.

Rationale Behind the FDA's New Rule

Before this federal regulation, 38 states in the U.S. had some form of breast density notification requirement. However, inconsistency across states and the absence of notification in some raised concerns, particularly among advocates for women whose advanced cancers had gone undetected due to dense breast tissue.

The FDA has standardized the information that women must receive, ensuring it is comprehensible at an eighth-grade reading level, which may help address disparities in understanding and reactions to breast density notifications, especially among women of color and those with low literacy.

The Value of Additional Screening

Standard mammograms use X-rays to produce two-dimensional images of the breast. Newer technology, known as tomosynthesis, generates three-dimensional images that can identify more cancers in women with dense breasts. Experts generally agree that women with dense breasts should opt for tomosynthesis screening when available.

While data suggests that supplementary screening using ultrasound, MRI, or contrast-enhanced mammography may reveal additional cancers, there is currently no conclusive evidence from randomized trials showing that such screenings lead to a reduction in breast cancer mortality. However, MRIs may detect early-stage cancers that could require less aggressive treatment.

Different professional organizations interpret existing data on supplementary screening in varying ways, leading to diverse recommendations. An important factor is a woman's personal risk level; emerging evidence indicates that women at higher risk of breast cancer may gain the most from supplementary screening.

What Should Women Consider Regarding Additional Screening?

Understanding personal risk is crucial when deciding on supplementary screening. The American College of Radiology advises women to undergo risk assessment by age 25. Tools like the Tyrer-Cuzick risk calculator, which is available online at no cost, can aid this process.

It's essential to recognize that breast density is just one of several risk factors for breast cancer, and many of the others can be modified. Engaging in regular physical activity, maintaining a healthy weight, reducing alcohol consumption, and consuming a vegetable-rich diet can all contribute to lowering breast cancer risk.

Potential Risks of Supplemental Screening

While the advantages of supplementary breast screening are widely discussed, the potential drawbacks receive less attention. The most frequent issue is false alarms, where results suggest possible cancer requiring follow-up. Occasionally, a biopsy may be necessary, which can induce anxiety, incur medical expenses, or lead to complications.

Supplementary screening could also result in overdiagnosis and overtreatment, meaning a cancer that would not have posed a threat might be identified and treated unnecessarily. MRI screenings utilize a contrast agent called gadolinium to enhance imaging, which the FDA considers safe for individuals with normal kidney function.

Furthermore, MRIs may uncover incidental findings outside the breast that require additional testing and costs. Women should weigh their tolerance for these risks against their desire for the potential benefits of more extensive screening.

Another consideration is the out-of-pocket cost of additional screenings beyond a mammogram. Only 29 states and the District of Columbia mandate insurance coverage for supplementary breast cancer screenings, with only three states—New York, Connecticut, and Illinois—requiring coverage without copays.

Further Learning and Resources

The FDA encourages women to engage in discussions with their healthcare providers; however, our research indicates that many women do not have these conversations, and many providers lack adequate knowledge about breast density and updated screening guidelines.

The reasons for this knowledge gap are unclear, but many healthcare providers report minimal training on breast density and express a lack of confidence in counseling patients about it. To help bridge this gap, radiologists may include recommendations for supplementary screening in their mammography reports to the referring healthcare provider.

Proactively seeking information about breast density and its implications can empower women to engage in informed discussions with their providers. Numerous online resources, including the American Cancer Society, Dense Breast-info, and the American College of Radiology, offer valuable information.

With a clearer understanding of the complexities surrounding breast density and its effect on breast cancer screening, women can have meaningful conversations about their personal risks with their healthcare providers and consider supplementary screening options, weighing the benefits and drawbacks of each.

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This article is provided by The Conversation, a nonprofit news organization dedicated to offering context on current events. Learn more about them or subscribe to their weekly newsletter.

Nancy Kressin has received funding from The American Cancer Society.

Christine M. Gunn is funded by the National Cancer Institute (1K07CA221899).

Priscilla Slanetz is a Principal Investigator for the Tomosynthesis Mammographic Imaging Screening Trial (TMIST) and serves on various boards, including the ACR Board of Chancellors.

Tracy A. Battaglia has received grant funding from the American Cancer Society and is a co-author on the ACR Appropriateness Criteria on Supplemental Breast Cancer Screening.

Breast Density and Cancer Risk - This video explores how breast density can impact cancer risk and emphasizes the importance of informed screening decisions.

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