BACKGROUND AND PURPOSE:

• There is a significant percentage of women with strong family history for breast cancer, but no known pathogenic genetic variant has yet been identified
• Saadatmand et al. (The Lancet Oncology, 2019) compared MRI with mammography for the detection of cancers in women at high risk for breast cancer based on family history

METHODS:

• Multicenter, randomized controlled trial (RCT)
  • Intention to treat
• Participants
  • Women aged 30-55 years
  • Cumulative lifetime breast cancer risk of ≥20% due to familial predisposition
  • BRCA1, BRCA2 and TP53 wild-type (no pathogenic variant identified)
  • No personal history invasive carcinoma
• Groups (1:1 randomization)
  • MRI group: Annual MRI & clinical breast exam | Biennial mammography
  • Mammography group: Annual mammography & clinical breast exam
• Registration group
  • If consent for randomization not obtained, women could still register for either MRI or mammography protocol in “joint decision with their physician”
  • This data only used in the analyses stratified by breast density
• Primary outcomes: Analysis of detected cancers (DCIS invasive)
  • Number | Size | Nodal status
• Secondary outcomes
  • False-positive results | Sensitivity and specificity | PPV of BI-RADS score ≥3 | PPV of biopsies

RESULTS:

• 1,355 women randomized | 231 registered without randomization
  • 675 of 1,355 women in MRI group | 680 to the mammography group
  • 218 of 231 registered (non-randomized) women were in mammography group | 13 were in the MRI group
• More breast cancers were detected in the MRI group (40) vs mammography (15) group (p=0.0017)
  • Screen detected cancers: MRI 98% | Mammography 87%
• Sensitivity was not statistically different between groups | Specificity was lower in MRI group (increased false-positives)
• Invasive cancers in the MRI group compared to mammography
  • Were smaller in the MRI group (p=0.010)
    • MRI group: Median size 9mm
    • Mammography group: 17 mm
  • Were less frequently node positive (p=0.023)
    • MRI group: 17%
    • Mammography group: 63%
• Tumor stages were significantly earlier in the MRI group during incident rounds (p=0.035)
  • Stage T1a and T1b cancers
    • MRI group: 48%
    • Mammography group: 7%
  • Stage T2 or higher
    • MRI group: 4%
    • Mammography group: 13%
• Node-positive tumors were less frequent in the MRI group (p=0.014)
  • MRI group: 11%
  • Mammography group: 63%
• Stage ≥T2 tumors were in the two highest breast density categories (C and D); p=0.0077
• One mortality reported from breast cancer during follow-up (mammography registration group)

CONCLUSION:

• For women at high familial risk, but negative genetic testing, MRI screening led to detection of cancers at an earlier stage than mammography which could impact
  • Choice and use of chemotherapy
  • Breast cancer-related mortality might be reduced with MRI screening
• MRI screening, consistent with previous studies, has a higher rate of  false-positive results (lower specificity), especially with high breast density
• Cost-effectiveness and breast cancer mortality will be reported in future analyses

Learn More – Primary Sources:

MRI versus mammography for breast cancer screening in women with familial risk (FaMRIsc): a multicentre, randomised, controlled trial

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