What further imaging is recommended for a woman with a BI‑RADS D (extremely dense) breast density?

Supplemental Imaging for BI-RADS D (Extremely Dense) Breasts

For women with BI-RADS D (extremely dense) breast tissue, supplemental screening with contrast-enhanced MRI is the most strongly recommended modality, as it demonstrates the highest cancer detection rate (16.5 additional cancers per 1,000 screened) and reduces interval cancer rates from 5.0 to 0.8 per 1,000, suggesting a mortality benefit. 1

Primary Recommendation: MRI with Contrast

The European Society of Breast Imaging now recommends supplemental screening with MRI in women with extremely dense breast tissue, regardless of risk stratification. 1 This represents the strongest current guideline recommendation based on:

• Superior sensitivity of 81-100%, far exceeding all other modalities 1, 2
• Significant reduction in interval cancers demonstrated in the DENSE trial, with interval cancer rates dropping from 5.0 per 1,000 (control group) to 0.8 per 1,000 (MRI group) 1
• Detection of smaller, less aggressive cancers that are lymph node negative and have better prognosis 1, 2
• Improved false-positive rates with subsequent screening rounds, dropping from 79.8 per 1,000 at baseline to 26.3 per 1,000 in the second screening round 1

Abbreviated MRI (AB-MRI) as an Alternative

AB-MRI offers comparable cancer detection with reduced cost and scan time, making it a practical alternative to full-protocol MRI. 1

• Cancer detection rate of 15.2 per 1,000 examinations compared to 6.2 per 1,000 with digital breast tomosynthesis alone 1, 3
• No statistical difference in sensitivity between standard MRI (100%) and AB-MRI (88.9%) 1
• Reduced specificity (87% vs 97% for DBT) means baseline imaging may result in benign biopsies or short-term follow-ups 1

Why Digital Breast Tomosynthesis (DBT) is Insufficient for BI-RADS D

DBT shows no significant increase in cancer detection specifically in women with extremely dense tissue, despite benefits in other density categories. 1

• Berg et al found the greatest increase in cancer detection with DBT occurred in heterogeneously dense breasts, not extremely dense breasts 1
• This highlights the critical need for other supplemental screening methods beyond DBT in the BI-RADS D population 1
• DBT should still be used as the primary screening modality (replacing standard 2D mammography), but supplemental imaging is essential 1, 2

Alternative Supplemental Options (When MRI Unavailable)

Contrast-Enhanced Mammography (CEM)

CEM shows promise with cancer detection rates of 8.6-13.1 per 1,000 screenings, though evidence is primarily from retrospective single-institution studies. 1

• Higher sensitivity than mammography alone, with statistically significant benefit in dense breast tissue 1
• The CMIST trial is currently enrolling to prospectively compare DBT and CEM in intermediate-risk women with dense breasts 1, 3
• May serve as an alternative for women seeking supplemental screening who cannot undergo MRI 1

Ultrasound (US)

Ultrasound is the least preferred supplemental option for BI-RADS D breasts and should only be considered when MRI is contraindicated or unavailable. 1, 4

• Lower cancer detection rate compared to MRI 4
• Substantially increased false-positive rate, with approximately 8-9 negative biopsies for every cancer detected 4
• Operator-dependent with limited field of view, creating practical implementation challenges 5

Risk Stratification Considerations

Risk assessment should be performed for all women by age 25 to guide supplemental screening choices beyond breast density alone. 2

• For high-risk women (≥20% lifetime risk): MRI with contrast is standard of care regardless of density 2, 4
• For intermediate-risk women (15-20% lifetime risk): MRI or AB-MRI are first-line supplemental options 1
• For average-risk women: The decision is more nuanced, as the U.S. Preventive Services Task Force concludes current evidence is insufficient to demonstrate that supplemental screening reduces breast cancer mortality or improves quality of life 2, though the DENSE trial's reduction in interval cancers suggests otherwise 1

Critical Caveats

All supplemental screening modalities increase false-positive results, recalls, and biopsies. 2

• For women aged 40-49 with extremely dense breasts screened annually for 10 years: 69% will receive at least one false-positive result versus 21% with biennial screening 2
• Unnecessary biopsy rates are 12% for annual screening versus 3% for biennial screening 2
• First-round MRI screening has higher false-positive rates that decrease substantially in subsequent rounds 3

Breast density classification can be inconsistent over time and between radiologists, with many women moving between "dense" and "nondense" classifications on sequential mammograms. 2

Modalities NOT Recommended

The following have insufficient evidence for supplemental screening in BI-RADS D breasts:

• MRI without IV contrast - no relevant literature supports this approach 1
• Abbreviated MRI without IV contrast - no relevant literature supports this approach 1
• Tc-99m sestamibi molecular breast imaging (MBI) - insufficient evidence currently, though emerging data exist 1
• FDG-PET breast dedicated - no relevant literature 1