Understanding Breast Density on Your Mammogram Report

In September 2024, the FDA mandated that breast density information be provided to patients on their mammography reports. This update to the Mammography Quality Standards Act (MQSA) is designed to help patients better understand their breast tissue and its role in cancer screening.

What Does It Require?

Patients must be notified if their breasts are classified as “dense” or “not dense.” Breast density is determined by the amount of fibroglandular (FG) tissue present:

• A: Almost all fatty (<25% FG tissue)

• B: Scattered areas of density (25–50% FG tissue)

• C: Heterogeneously dense (51–75% FG tissue)

• D: Extremely dense (>75% FG tissue)

Patients must also be informed that dense breast tissue (types C and D):

1. Increases a patient’s lifetime risk of developing breast cancer.

2. Reduces the sensitivity of mammography, making it harder to detect cancers that may be present.

The notification must further inform patients that:

1. Supplemental imaging tests (such as ultrasound, digital breast tomosynthesis, or MRI) may help detect cancers that mammography might miss.

2. Patients are encouraged to discuss their individual risk and screening options with their healthcare provider.

What This Means for Patients with Dense Breasts

Some patients may benefit from both mammography and another imaging modality like MRI, particularly those with extremely dense breast tissue. In the U.S.:

• 47% of women have dense breast tissue (C or D)

• 10% have extremely dense breast tissue

However, many medical societies have not issued formal guidelines for supplemental imaging due to limited long-term outcome data from U.S.-based randomized trials.

Potential Downsides of Supplemental Imaging

• Increased supplemental imaging can lead to false positives and unnecessary biopsies.

• Insurance coverage for supplemental imaging is not universally mandated and varies by state and insurer. MRIs can cost $1,000–$2,000 out of pocket.

Determining Your Breast Cancer Risk

Shared decision-making between a patient and their healthcare provider is essential to determine the most appropriate screening plan. Breast cancer is multifactorial, so it’s important to consider personal risk factors:

• Personal history of breast cancer

• Family history of breast or ovarian cancer

• Genetic mutations (BRCA1/2, PALB2, CDH1)

• Dense breast tissue

• Younger age at first menstrual cycle

• Later menopause

• Nulliparity (no pregnancy history)

• Increasing age

• High BMI

• Heavy alcohol or smoking history

Resources for More Information

For additional guidance on breast cancer and screening recommendations, patients can visit:

• American Cancer Society

• Susan G. Komen Foundation

• BreastCancer.org

• American Breast Cancer Foundation

• United States Preventive Task Force

• American College of Obstetricians and Gynecologists

Next Steps

Understanding your breast density is an important step in proactive breast health. Discuss your individual risk and screening options with your healthcare provider to make informed decisions about supplemental imaging. Taking charge of your screening strategy helps ensure early detection and the best possible outcomes.