Overview

• Since September 2024, mammogram reports must disclose a patient’s breast density and note the potential need for additional imaging under federal rules.
• About 40% of women have dense breasts, a designation that can change over time and does not correlate with breast size, according to the American Cancer Society.
• The American College of Radiology says dense tissue confers roughly a two- to threefold higher risk of breast cancer and can mask tumors because both appear white on mammograms.
• Clinicians recommend annual mammograms starting at 40 and an individualized risk assessment to decide on add-ons such as 3D tomosynthesis, ultrasound, MRI, or contrast-enhanced mammography.
• A Glamour author’s cancer was detected by MRI after mammograms and ultrasound missed it, highlighting how supplemental imaging can find cancers in dense tissue despite the risk of false positives.