BACKGROUND AND PURPOSE:

• Bakker et al. (NEJM, 2019) investigated whether supplemental MRI reduced interval breast cancers in women with dense breast tissue
  • Assumption that reduction in interval cancers signifies earlier detection prior to a tumor becoming symptomatic

METHODS:

• Multicenter, randomized, controlled trial (RCT)
  • Dense Tissue and Early Breast Neoplasm Screening (DENSE) trial
  • Results from the initial 2 years
• Setting
  • The Netherlands
• Participants
  • Between ages 50 and 75 years
  • Extremely dense breast tissue and normal mammography results
• Groups
  • MRI-invitation group: Invited to undergo supplemental MRI (did not have to undergo MRI)
  • Control group: Mammography screening only
• Primary outcome
  • The between-group difference in the incidence of interval cancers during the 2-year screening period

RESULTS:

• 40,373 women were included (1:4 randomization)
  • MRI group
    • 8061 patients invited | 59% accepted invitation
    • 454 recalled for suspicious findings
    • 300 biopsies performed
    • 79 cancers were detected
  • Control group: 32,312
• The interval-cancer rate was lower in the MRI-invitation group than the control group (P<0.001)
  • MRI group: 2.5 per 1000 screenings
  • Control group: 5.0 per 1000 screenings
• Of the 20 interval cancers that were diagnosed in the MRI-invitation group
  • 4 were diagnosed in the women who actually underwent MRI (0.8 per 1000 screenings)
  • 16 in those who did not accept the invitation (4.9 per 1000 screenings)
• MRI cancer-detection rate among the women who actually underwent MRI screening was 16.5 per 1000 screenings (95% CI, 13.3 to 20.5)
• PPV (number of cancers detected)
  • 17.4% (95% CI, 14.2 to 21.2) for recall for additional testing
  • 26.3% (95% CI, 21.7 to 31.6) for biopsy
• False positive rate: 79.8 per 1000 screenings
• Tumors in the MRI group were more likely to be
  • Smaller | Node negative | Earlier stage
• 0.1% of women who underwent MRI had either an adverse event or a serious adverse event during or immediately after the screening
  • Vasovagal reactions to the MRI procedure or reaction to contrast

CONCLUSION:

• The addition of MRI screening for women with extremely dense breast tissue resulted in significantly fewer interval cancers vs mammography alone
• However, this study does not address whether a decrease in interval cancers will lead to improved survival
  • The authors plan to continue this study to determine impact on rate of advanced cancers and mortality

Learn More – Primary Sources:

Supplemental MRI Screening for Women with Extremely Dense Breast Tissue

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