What are the screening recommendations for a woman with high fibroglandular density?

Screening Recommendations for Women with High Fibroglandular Density

Women with high fibroglandular density should undergo annual digital breast tomosynthesis (DBT) starting at age 40, with supplemental breast MRI or abbreviated MRI (AB-MRI) as the preferred additional screening modality to maximize cancer detection and reduce interval cancers. 1, 2

Primary Screening Foundation

• Continue annual mammography (preferably DBT) as the essential baseline screening starting at age 40, as mammography reduces breast cancer mortality by more than 40% even in women with dense breasts 1
• DBT specifically demonstrates the greatest increase in cancer detection rates in women with heterogeneously dense breasts compared to other density categories, with an incremental detection of 1.6 to 3.2 cancers per 1,000 examinations over standard digital mammography 1, 2
• Dense breast tissue reduces mammographic sensitivity to as low as 63% compared to 87% in fatty breasts, making supplemental screening particularly important 2

Risk Stratification Is Critical

Before recommending supplemental screening, perform formal breast cancer risk assessment by age 25 using validated models (such as the modified Gail model or BRCAPRO) to determine the appropriate intensity of supplemental screening 1, 3

The relative risk for breast cancer varies by density level:

• Heterogeneously dense breasts: 1.2-1.3 times increased risk compared to average density 1, 2
• Extremely dense breasts: 2.1 times increased risk compared to average density 1

Some providers now consider women with extremely dense breasts to no longer be "average risk" given this substantial elevation 1

Supplemental Screening Algorithm

For Women with Heterogeneously or Extremely Dense Breasts:

First-line supplemental screening: Breast MRI with contrast or abbreviated breast MRI (AB-MRI) 1, 2

• AB-MRI demonstrates a cancer detection rate of 15.2 per 1,000 examinations compared to only 6.2 per 1,000 with DBT alone in women with dense breasts 2, 3
• The DENSE trial showed supplemental MRI reduced interval cancer rates from 5.0 to 0.8 per 1,000 screenings in women with extremely dense breasts 2
• Cancers detected by MRI tend to be smaller, lymph node-negative, and less biologically aggressive, potentially improving outcomes 2, 4
• The European Society of Breast Imaging recommends MRI screening every 2-4 years for women aged 50-70 with extremely dense breasts 1

Alternative supplemental screening: Whole breast ultrasound (if MRI is contraindicated, unavailable, or unaffordable) 2, 3

• Ultrasound detects an additional 3.3-7.7 cancers per 1,000 examinations 1, 3
• Major caveat: Ultrasound substantially increases false-positive biopsies, reducing positive predictive value from 22.6% for mammography alone to 11.2% when ultrasound is added—approximately 8-9 negative biopsies occur for every cancer detected 3
• Ultrasound should never replace mammography as it does not detect microcalcifications, which are often the only sign of ductal carcinoma in situ 3

Emerging option: Contrast-enhanced mammography (CEM) 2

• Shows promise with cancer detection rates of 8.6-13.1 per 1,000 examinations 2
• The ongoing CMIST trial is comparing DBT and CEM in women with dense breasts 2

Important Implementation Considerations

Federal law now requires notification: The FDA mandates that women be informed of their breast density status and that supplemental imaging may be beneficial 2, 4

Counsel patients about false-positive rates: First-round supplemental MRI screening may result in higher false-positive rates, but these decrease substantially in subsequent screening rounds 2

Do not use ultrasound as first-line in high-risk women: For women meeting high-risk criteria (≥20% lifetime risk), MRI is superior and recommended regardless of density 3

Consider volumetric measurements: Fibroglandular volume and percent fibroglandular volume are more accurate predictors of breast cancer risk than percent dense area alone, with odds ratios of 2.9 and 4.1 respectively for highest versus lowest quintiles 5

Common Pitfalls to Avoid

• Do not assume all women with dense breasts need supplemental screening—risk stratification beyond density alone is essential 3
• Do not fail to continue annual mammography—supplemental screening is additive, not a replacement 3
• Do not use ultrasound in women with non-dense breasts—the incremental cancer detection rate is 0 per 1,000 examinations in this population 1
• Do not ignore patient preferences regarding false-positive burden—discuss the trade-off between increased cancer detection and increased callbacks/biopsies 3