When to consider Magnetic Resonance Imaging (MRI) of the breast for women with dense breast tissue?

From the Guidelines

MRI breast screening should be considered for women with dense breasts who have additional risk factors for breast cancer, such as a personal history of breast cancer, a strong family history of breast cancer, known genetic mutations like BRCA1 or BRCA2, a history of chest radiation therapy before age 30, or a calculated lifetime risk of breast cancer greater than 20%.

Key Considerations

• The American College of Radiology recommends annual breast MRI surveillance for women with a lifetime risk of breast cancer of 20% or greater 1.
• Women with a personal history of breast cancer and dense breasts, as well as those diagnosed with breast cancer before age 50, may benefit from annual breast MRI surveillance 1.
• MRI is not routinely recommended for all women with dense breasts alone, as this would lead to many false positives, unnecessary biopsies, and increased healthcare costs.
• For women with dense breasts but no additional risk factors, supplemental ultrasound screening may be considered as an alternative.

Screening Recommendations

• If MRI is recommended, it should be performed in addition to, not instead of, regular mammography, typically once per year 1.
• Insurance coverage for breast MRI varies, so checking with your provider about coverage is advisable before proceeding.

Risk Factors

• A personal history of breast cancer
• A strong family history of breast cancer (especially in first-degree relatives)
• Known genetic mutations like BRCA1 or BRCA2
• A history of chest radiation therapy before age 30
• A calculated lifetime risk of breast cancer greater than 20%

Additional Considerations

• The sensitivity of MRI allows it to detect cancers that might be missed on mammography in dense breast tissue, which contains more fibrous and glandular tissue that appears white on mammograms, similar to how cancer appears 1.
• The American Cancer Society has recommended annual breast MRI for breast cancer screening in high-risk women since 2007 1.

From the Research

Considerations for MRI of the Breast in Women with Dense Breast Tissue

• Women with dense breast tissue are at a higher risk of breast cancer, and the sensitivity of mammography in this group is reduced due to the masking effect of overlapping tissue 2.
• The American Cancer Society (ACS) guidelines issued in 2007 recommend neither for nor against screening MRI in women at intermediate breast cancer risk (15%-20%), including those with dense breast tissue 3.
• However, multiple investigations have found that women at intermediate risk may be suitable candidates for screening MRI, given the high detection rates of early-stage cancers and acceptable false-positive rates 3.
• For women with dense breast tissue, the Dense Tissue and Early Breast Neoplasm Screening trial reported that the incremental cancer detection rate (CDR) by MRI exceeded 16 cancers per 1000 examinations 3.
• Breast MRI is the most supported modality for supplemental screening in women with extremely dense breasts, with sensitivity ranging from 81% to 100% 2.

High-Risk Women

• Guidelines recommend that women with 20% or greater lifetime risk of breast cancer undergo annual breast MRI screening to supplement mammography, irrespective of age 4.
• Women at high risk for breast cancer are defined as genetic carriers of the more commonly known breast cancer genes (BRCA1, BRCA2 TP53), first degree relatives of carriers, women with varying degrees of high risk family histories, and/or women with greater than 20% lifetime risk for breast cancer based on existing risk models 5.
• Breast MRI screening in high-risk women under 40 yielded elevated cancer detection rates (11.7/1000) 4.

Screening Recommendations

• The NCCN recommends considering breast MRI as an adjunct to annual mammography and clinical breast examination for women who have a BRCA1 or -2 mutation or who have a first-degree relative who has a BRCA1 or -2 mutation but who have not undergone genetic testing themselves 6.
• MRI is also recommended for patients who underwent radiation treatment to the chest between 10 and 30 years of age, and in those who carry or have a first-degree relative who carries a genetic mutation in the TP53 or PTEN genes (Li-Fraumeni, Cowden, and Bannahyan-Riley-Ruvalcaba syndromes) 6.