Breast Density

How I Practice Video Series
Sharon Mass, MD, FACOG

HIP: Breast Density from ACOG on Vimeo.


One of the issues that I’ve recently had to discuss is the issue of breast density and what that means to the patient. Breast density refers to the relative amount of fatty tissue and fibroepithelial or connective tissue in the breast. The breast density is described in one of four categories on the mammogram: completely fatty, scattered fibroglandular elements, heterogeneously dense, or extremely dense. The latter two categories are lumped into the category of “dense breasts”. The issue is that increased breast density may impact the ability to read a mammogram in one of two ways. First, is that the density can mask the detection of cancer on the mammogram and second, for the patient, it may actually be an independent slight risk factor for breast cancer. Recently, there has been legislation mandating that the ordering physician discuss breast density with his or her patients in several states. When I’m discussing breast density with a patient, what I try to do is to educate them about their personal level of breast density but also to assess other risk factors for breast cancer to try to put the picture together for optimal screening for that patient. So we will assess their personal history, of pre-cancerous lesions, we’ll assess their family history, prior radiation therapy, mutations, or other factors that may increase their risk of breast cancer. Specific to breast density, one of the issues is knowing what to do with the information about an individual’s level of density. There are some organizations that recommend screening ultrasounds for all women with dense breasts. However, the problem with this is for every 1,000 women screened by ultrasound, 300 of them are going to require a biopsy and only a very small percentage of those will actually find cancer. Thus, the patient is undergoing a costly procedure both in terms of expense and in terms of fear and anxiety in response to the additional screening. Neither the American College of OB/GYNs nor the American College of Radiology recommends additional screening at this time solely on the basis of breast density. When we assess a patient’s risk, if the patient does fall into a high risk category meaning that they have a 20% lifetime risk of breast cancer or if they have dense breasts and at least a 15% lifetime risk of breast cancer. Sometimes I will recommend additional testing in the form of magnetic resonance imaging or MRI, or would discuss with that patient initial screening the new modality called digital breast tomosynthesis. Digital breast tomosynthesis, commonly known as 3D mammography, has been shown to increase breast cancer detection while decreasing recalls and biopsies because it eliminates the view of some overlapping tissue and may better clarify the reading of the mammogram for the radiologist. Overall, what I try to do is to put the patient’s personal breast density and her other risk factors into a context where we can decide what the optimal plan for that patient is, educate her on what breast density means, and how she should move forward, and come up with a plan that will best assess that patient’s risk of breast cancer. This is how I practice.


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