Increased breast density is an important risk factor in the development of breast cancer, and is now being factored into lifetime risk assessment. Furthermore, the impact of dense breast tissue is being increasingly recognized for decreasing the sensitivity of screening mammograms, and this could shape future recommendations for mammographic screening guidelines in certain high-risk populations.
Educational Goals / Teaching Points
This educational poster explores the impact of mammographic breast density by
1. Explaining the pathophysiology of breast density.
2. Reviewing the Bi-RADS classification system for classifying breast density and other quantitative methods for measuring breast density.
3. Discussing the impact of breast density on developing and detecting breast cancer.
4. Exploring the impact of breast density on screening guidelines and alternate screening methods that could be used in the future.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Annual mammographic screening is recommended for women over the age of 40, or biannually for women between the ages of 50 to 74. Screening mammography has a sensitivity between 68% and 90% for detecting cancers, however sensitivity is lower in women with mammographically dense breast tissue. (1) Based on the BI-RADS classification of breast tissue density, around 50% of women have heterogeneously dense or extremely dense breast tissue. Therefore, half of the screening population has dense breast tissue, which not only increases risk of developing breast cancer, but also makes screening more difficult. Alternate screening methods are being explored to target this population. Digital breast tomosynthesis has already shown an increase in cancer detection rates and reduction in recall rates compared to traditional two-dimensional digital mammography. (3) Whole breast ultrasound and breast MRI are other emerging modalities that may be beneficial supplemental screening methods in women with dense breasts who are also at increased lifetime risk of developing breast cancer. (2,3)
Breast density is being increasingly recognized as an important risk factor in the development of breast cancer and is now being factored into lifetime risk calculators. It is important for radiologists-in-training to develop an understanding of mammographic breast density and how this impacts current screening methods. Supplemental screening modalities for women with dense breast tissue is an emerging area of interest in breast imaging.