Information on Breast Density

Starting January 1, 2014, North Carolina law requires that patients be informed if they have “dense breast tissue” on screening mammography, and if so, that they may want to discuss this with their primary physician. Unfortunately the law does not mandate insurance coverage for any additional screening studies. Approximately 50% of women undergoing screening mammography are classified as having either “heterogeneously dense” or “extremely dense” breasts. For all of these women, the patient letter will inform them that they have “dense breast tissue.” Only 10% of all women have “extremely dense” breast tissue, which is associated with a relative risk of breast cancer of approximately 2 compared with average breast density. 40% of women have “heterogeneously dense” breast tissue, which is associated with a relative risk of approximately 1.2. Therefore, breast density is not a major cancer risk factor.

• The sensitivity of mammography is reduced as background breast tissue density increases.
• The recommendations for screening mammography are exactly the same for women with dense breasts as for the rest of the population. Mammography is the only screening modality that has undergone randomized controlled trials demonstrating a reduction in breast cancer mortality. There is no recommendation that it be replaced with another test in any subset of the population.
• For patients who are interested in additional screening options, a breast cancer risk assessment may be appropriate. There are several models on which this can be calculated. This would be a good starting point in the discussion of whether supplemental tests would be beneficial, and whether your insurance company will cover the cost.

Additional breast imaging “screening options” which we offer, include screening MRI and Hologic Genius™ 3D mammography.

• 3D mammography is offered at all of our imaging centers. Data to date has been very promising in improving breast cancer detection in women of all breast densities. 3D mammography has improved the breast cancer detection up to 50% in some studies.
• Screening breast MRI has been shown to substantially increase the rate of cancer detection.  It is an expensive study and most insurance companies will cover the exam in only high risk patients.  It is recommended in patients who are at very high risk (>20% lifetime risk) based on American Cancer Society guidelines. For patients at “intermediate risk,” such as those with a personal history of breast cancer or a prior biopsy diagnosis of atypia (equivalent to a 15% to 20% lifetime risk), a patient-centered shared decision-making approach is recommended.
• Screening breast ultrasound is not offered at most, if any, centers in North Carolina. Given the higher sensitivity of breast MRI, the high number of associated unnecessary biopsies and follow up exams, and the technical limitations of providing routine screening breast ultrasound, this is not currently recommended for screening by the Society of Breast Imaging & American College of Radiology.

For more information, please refer to the North Carolina Breast Density Information page and review the American College of Radiology’s Breast Density Brochure.