Is the new mammography technique comparable to conventional digital mammography regarding sensitivity, specificity, and cancer detection rates?

Digital Breast Tomosynthesis (DBT) is Superior to Conventional Digital Mammography

Digital breast tomosynthesis (DBT) demonstrates superior performance compared to conventional digital mammography (DM), with significantly higher cancer detection rates, improved sensitivity and specificity, and reduced false-positive recall rates across most screening populations.

Performance Metrics: DBT vs. Conventional Mammography

Cancer Detection Rates

DBT consistently outperforms conventional DM in detecting breast cancers:

• DBT + DM detects 6.4-7.4 cancers per 1,000 screened versus 4.7 per 1,000 with DM alone 1
• The randomized TOSYMA trial showed invasive cancer detection of 7.1 per 1,000 with DBT versus 4.8 per 1,000 with DM 1
• Meta-analyses confirm DBT increases cancer detection by approximately 29-41%, with the increase predominantly in invasive cancers rather than ductal carcinoma in situ 2

Sensitivity and Specificity

The diagnostic accuracy improvements are substantial:

• Sensitivity: DBT achieves 96.4% versus 71.4% for conventional DM (p=0.008) 3
• Specificity: DBT reaches 92.3% versus 90.0% for DM (p<0.001) 3
• In diagnostic settings, DBT demonstrates 100% sensitivity compared to 73.5% for DM 4

Recall Rates (False Positives)

DBT significantly reduces unnecessary callbacks:

• Recall rate reduced from 12.0% to 8.4% with DBT (p<0.01) 5
• The TOSYMA trial showed a 15.6% reduction in false-positive recalls at first screening round 1
• Positive predictive value increases by 4.9% with DBT 1

Population-Specific Benefits

Dense Breast Tissue

DBT provides the greatest advantage in women with dense breasts, where conventional mammography sensitivity drops to 50%:

• Recall rates significantly reduced in scattered fibroglandular, heterogeneously dense, and extremely dense breasts 5
• Greatest improvement in sensitivity and specificity occurs in dense breast tissue 6

Women Under Age 50

Younger women experience particularly pronounced benefits:

• Significant recall rate reductions for women <40 years, 40-49 years, 50-59 years, and 60-69 years 5
• Benefits especially pronounced in women under 50 7

Personal History of Breast Cancer

For breast cancer survivors at higher risk of second cancers:

• DBT maintains 96.4% sensitivity versus 71.4% for DM 3
• Recall rate reduced from 11.0% to 7.9% in lumpectomy patients (p=0.002) 3
• Particularly beneficial in women with nondense breasts post-treatment 3

Clinical Implementation Considerations

Reading Time and Workflow

The primary tradeoff is increased interpretation time:

• Reading time approximately doubles with DBT compared to DM 1
• However, AI-assisted reading can reduce DBT reading time by 53.1% (from 122.6 to 57.5 seconds) while maintaining diagnostic accuracy 8

Radiation Dose

• DBT with synthetic mammography (SM) reduces radiation dose by 39% compared to DBT + conventional DM (1.73 vs 2.84 mGy) 8
• Synthetic mammography generated from DBT data performs equivalently to conventional 2D images 7

Guideline Recommendations

Current ACR guidelines support DBT implementation:

• DBT screening is "usually appropriate" for average-risk, intermediate-risk, and high-risk women across all breast density categories 6, 9
• DBT recommended as supplemental screening in organized programs 10

Critical Caveats

Overdiagnosis Concerns

While most additional cancers detected are invasive (favorable), long-term mortality benefit from DBT has not yet been proven in randomized trials 2. The increase in invasive cancer detection (+41%) without increase in DCIS is reassuring but requires continued surveillance.

Interval Cancer Data

Only limited data exist on interval cancer rates with DBT:

• Two studies showed non-significant reductions (0.7 to 0.5 per 1,000 and 0.6 to 0.46 per 1,000) 2
• Interval cancer rate serves as a proxy for mortality reduction effectiveness

Cost and Availability

Equipment availability and increased radiologist time requirements remain practical barriers to universal implementation.

Bottom Line Algorithm

Use DBT over conventional DM when:

1. Available equipment and trained radiologists exist
2. Patient has dense breast tissue (heterogeneously or extremely dense)
3. Patient is under age 50
4. Patient has personal history of breast cancer
5. Screening program can accommodate increased reading time

DBT + synthetic mammography is the optimal approach, eliminating need for additional 2D views while reducing radiation dose and maintaining diagnostic performance 8.