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Educate patients about dense breasts and cancer risk

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Approximately one-third of cancers in dense breasts have a delayed diagnosis on mammography, and 70% of cancers occur in dense breasts, emphasizes radiologist at annual ACOG meeting



Monica Saini, MD, a radiologist in Santa Fe, New Mexico, and JoAnn Pushkin, executive director of the nonprofit educational website, engaged ObGyn attendees on “Breast density: Why it matters and what to do” at the American College of Obstetricians and Gynecologists (ACOG) 2017 Annual Clinical and Scientific Meeting (May 6–9, 2017) in San Diego, California. The program was sponsored by GE Healthcare.


Breast density is the second largest risk factor for breast cancer after radiation treatment to the chest, so it is important to identify patients with dense breasts, according to Dr. Saini. The American College of Radiology’s Breast Imaging Reporting and Data System (BI-RADS) classifies breast density into 4 groups: 1) almost entirely fatty, 2) scattered fibroglandular densities, 3) heterogeneously dense, and 4) extremely dense. A woman whose mammograms show heterogeneously dense or extremely dense breasts is considered to have “dense breasts.”

Cancer is often difficult to identify with mammography in dense breasts because masses or lumps appear as white on a white (dense tissue) background; by contrast, a tumor in a nondense (fatty) breast would appear as white on a dark, fatty tissue background. Approximately one-third of cancers in dense breasts have a delayed diagnosis on mammography, and 70% of cancers occur in dense breasts, said Dr. Saini.

Having dense breasts is not an abnormal condition, however, and is actually common—about 40% of women aged 40 or older have dense breasts.

Supplement mammography with other screening modalities

While screening mammograms can save lives, mammography should not be viewed as a one-size-fits-all modality. Screening for breast cancer should be personalized, based on, among other factors, a woman’s personal and family history, age, genetic risk, lifestyle factors, and breast density.

Key point. Women with dense breasts should continue to have screening mammograms. In addition, mammography for these patients should be supplemented with other technologies, such as 3D mammography (digital tomosynthesis), handheld ultrasound, or automated breast ultrasound (ABUS). In women at higher risk (presence of BRCA1 or BRCA2 gene mutation, strong family history of breast cancer, or radiation treatment to the chest) magnetic resonance imaging (MRI) may be considered.

Data on adjunct screening modalities. Dr. Saini discussed the results of the ASTOUND trial, a prospective multicenter study that compared ultrasound and tomosynthesis for the detection of breast cancer in mammography-negative dense breasts.1 Among the 3,231 asymptomatic women included in the trial, 13 breast cancers were detected with tomosynthesis (incremental cancer detection rate [CDR], 4 per 1,000 screens; 95% confidence interval [CI], 1.8–6.2) and 23 were detected with ultrasound (incremental CDR, 7.1 per 1,000 screens; 95% CI, 4.4–10.0), P = .006. There were 107 false-positive results: 53 with tomosynthesis and 65 with ultrasound, a difference that was not statistically significant. The study authors noted that while ultrasound had better incremental breast cancer detection than tomosynthesis, and at a similar false-positive recall rate, tomosynthesis did detect more than half of the additional breast cancers in these women.1

Make screening easier for the patient

Dr. Saini noted that for women with dense breasts, performing mammography and adjunctive screening at the same visit is convenient for the patient. Physicians can also write prescriptions for follow-up based on density findings, for example, “3D mammography if available, if dense, order ultrasound.”

Read how to answer patient questions about breast density


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