What are the implications of dense breasts on a mammogram?

From the Guidelines

Women with dense breasts on a mammogram should continue with regular mammogram screenings and consider additional screening methods, such as 3D mammography (tomosynthesis) or ultrasound, to improve cancer detection rates. Dense breast tissue can make it harder to detect cancer on mammograms since both dense tissue and tumors appear white 1. The sensitivity of mammography in women with dense breast tissue can be as low as 30% 1.

Screening Recommendations

• Women with dense breasts should discuss their personal risk factors with their healthcare provider to determine the best screening approach 1.
• Additional screening methods, such as 3D mammography (tomosynthesis) or ultrasound, may be beneficial for women with dense breasts to improve cancer detection rates 1.
• The American College of Radiology (ACR) recommends annual screening mammography beginning no later than 40 years of age for women at intermediate risk 1.

Breast Density and Cancer Risk

• Dense breast tissue is a risk factor for breast cancer and can complicate early detection through standard mammography 1.
• Women with extremely dense breasts have a higher relative risk of developing breast cancer, with a relative risk of 2.1 compared to women with average breast density 1.
• The ACR recommends that women with dense breasts be notified of their breast density and discuss their screening options with their healthcare provider 1.

Supplemental Screening Options

• 3D mammography (tomosynthesis) has been shown to increase cancer detection rates and decrease recall rates compared to digital mammography alone 1.
• Ultrasound may also be a useful supplemental screening tool for women with dense breasts, particularly those at high risk of breast cancer 1.
• MRI may be recommended for women with a high risk of breast cancer, such as those with a family history of breast cancer or a personal history of breast cancer 1.

From the Research

Dense Breasts on Mammogram

• Dense breasts are associated with a modestly increased risk of breast cancer and reduced sensitivity of mammography to detect breast cancer 2
• The American College of Obstetricians and Gynecologists does not recommend routine use of alternative or adjunctive tests to screening mammography in women with dense breasts who are asymptomatic and have no additional risk factors 2

Screening Options

• Mammography is the gold standard for breast cancer screening, but supplemental screening with ultrasound and magnetic resonance imaging (MRI) may be considered for women with dense breasts 3, 4
• Breast MRI has the highest sensitivity for breast cancer detection among current clinical imaging modalities and is indispensable for breast imaging practice 5
• Supplemental screening can increase breast cancer detection in women with dense breasts, but carries a risk of increased false-positive test results 6

Guidance for Healthcare Providers

• There are currently no clear guidelines for providers or patients on recommendations for supplemental screening after a mammogram finding of heterogeneously or extremely dense breasts on mammography 6
• Standardizing recommendations and implementation of risk-based decision-making using a validated calculator would allow for earlier detection of breast cancer, clear guidance for providers, and ensure equitable care for patients 6
• Women at higher risk for developing breast cancer would benefit most from supplemental screening 6