BACKGROUND AND PURPOSE:

• Mammography is the only test with evidence demonstrating breast cancer mortality reduction
• MRI is recommended for women at high risk for breast cancer (for example, those with BRCA mutations or others with >20% lifetime risk)
• Current guidelines recommend annual mammography for women with treated breast cancer and restricts the use of MRI screening to those at high risk
• Buist et al. (JAMA Internal Medicine 2018) measured the biopsy rates and yield in the 90 days following screening (mammography vs MRI) in women with a personal history of breast cancer and based on breast cancer risk in women without personal history

METHODS:

• Observational cohort study
  • Data from 6 Breast Cancer Surveillance Consortium (BCSC) registries
• Participants
  • Women with ≥ 1 screening digital mammogram or screening breast MRI from 2003 to 2013
• Women received either
  • Mammogram alone
  • MRI with or without mammogram within 30 days
• Primary outcomes (within 90 days of screening episodes)
  • Biopsy intensity (most invasive procedure type)
  • Biopsy yield (most invasive finding)
• Outcomes were stratified by
  • Personal history of breast cancer
  • BCSC 5-year breast cancer risk among women without personal history of breast cancer

RESULTS:

• 812,164 women undergoing screening were included with a total of 2,048,994 imaging episodes
  • Women with personal history received 101,103 mammograms and 3,763 MRI screens
  • Women without personal history received 1,939,455 mammograms and 4673 MRI screens
• In women with personal history, age-adjusted core and surgical biopsy rates (per 1000 episodes) doubled in MRI group (57.1; 95% CI, 50.3-65.1) vs mammography (23.6; 95% CI, 22.4-24.8)
• In women without personal history, age adjusted core and surgical biopsy rates (per 1000 episodes) were 5 times higher following MRI (84.7; 95% CI, 75.9-94.9) vs mammography (14.9; 95% CI, 14.7-15.0)
• In women with personal history, ductal carcinoma in situ and invasive biopsy yield (per 1000 episodes) were higher following mammography (404.6; 95% CI, 381.2-428.8) compared with MRI (267.6; 95% CI, 208.0-337.8)
• Women without a personal history showed a similar but nonsignificant trend
• High-risk benign lesions were more commonly identified following MRI regardless of personal history
• Higher biopsy rates and lower cancer yield following MRI were not explained by increasing age or higher 5-year breast cancer risk

CONCLUSION:

• Higher biopsy rates were expected with MRI because of its higher sensitivity and lower specificity compared with mammography
  • Unlike positive mammography which is usually followed by further targeted mammography or ultrasound, positive screening MRI results are usually resolved with short-interval follow-up MRI or biopsy
• Women with and without personal history had higher biopsy rates and lower cancer yield findings after undergoing a screening MRI experience
• Authors point out that this is study looked at 90 day rates, while traditional screening performance takes in to account examination interpretation within 12 months follow-up for cancer outcomes
• In addition, the authors state that “further work is needed to identify women who will benefit from screening MRI to ensure an acceptable benefit-to-harm ratio.”

Learn More – Primary Sources:

Breast Biopsy Intensity and Findings Following Breast Cancer Screening in Women With and Without a Personal History of Breast Cancer

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Mammography Guidelines for Average-Risk Women

Atypical Hyperplasia of the Breast: Follow-up and Management