Dense Breast Tissue: What To Do?

What is dense breast tissue?

Breasts are made up of different types of tissue: Fibrous or connective tissue that holds the breast in place; glandular tissue, which includes lobules and ducts that produce and transport milk; and fatty tissue that fills the space between fibrous and glandular tissue and helps give breasts their size and shape. Breast density is a measure of how much fibrous and glandular tissue (referred to as fibroglandular tissue) there is in the breast relative to fat tissue. If you have higher breast density, it means that your breasts are comprised of more fibroglandular tissue compared to fat.

Dense breast tissue is normal and occurs in nearly half of women over the age of 40. On average, breast density is higher in women under the age of 40 and tends to decrease as women get older; 40 percent of women in their 50s and 25 percent of women aged 60 and over have dense breasts.

How do I know if I have dense breast tissue?

The determination is made by a radiologist, who reviews a mammogram and assesses the proportion of white, gray, and black areas on the image. Fibroglandular tissue appears white on a mammogram, so the greater proportion of white there is on the image, the denser the breasts. 

As of September 2024, the FDA requires that all mammogram facilities nationwide include a breast density statement in a patient’s report. That statement designates the patient’s breasts as dense or not dense and describes how breast density can influence the interpretation of a mammogram. Prior to this rule, reporting standards for dense breast tissue varied from state to state, and several did not require any patient notification.

Why is it important to know if you have dense breasts?

Breast density is just one factor associated with an elevated breast cancer risk. Researchers are still trying to understand the underlying links between dense breasts and cancer. Breast cancer is known to develop in glandular tissue, so having a greater amount of it may simply provide more opportunity for abnormal cells to grow.

Higher breast density can also make it more challenging for radiologists to see abnormal growths since they both appear white on a mammogram. Dense breast tissue can effectively “cloud” the mammogram and increase the likelihood that a potentially cancerous growth or tumor is missed. 

How is dense breast tissue categorized?

Doctors use a system developed by the American College of Radiology (ACR) called Breast Imaging Reporting and Data System (BI-RADS) to interpret and report standardized mammogram findings. It is subjective in nature, so doctors are increasingly using automated software to assist in the classification process. BI-RADS classifies dense breasts into four categories:

Category A is for breasts composed entirely or almost entirely of fatty breast tissue. The mammogram from this breast will appear mostly dark gray or black and may have small amounts of dense breast tissue that appear light gray or white. About 10 percent of women fall into this category.

Category B is defined by scattered areas of dense breast tissue. A Category B mammogram will have both light and dark gray or black areas. Tumors can be obscured in areas of the breast that appear dense. About 40 percent of women fall into category B.

Category C is comprised of heterogeneously dense breasts. On a mammogram, these breasts will appear mostly light gray or white. About 40 percent of women fall into this category.

Category D is defined as extremely dense breasts. Most of the breast is made up of dense breast tissue, and the mammogram appears almost completely white. Ten percent of women fall into Category D.

Women in categories C and D are considered to have dense breasts.

How should dense breasts be screened for breast cancer?

Dense breasts make standard mammograms—also called 2D mammograms because they are a two-dimensional image of a three-dimensional breast—more challenging for radiologists to spot potential cancer. Experts do not currently agree what secondary tests, if any, should be done across all women with dense breasts to screen for the disease. The following screening tests are most commonly recommended for women who have extremely dense breast tissue as determined by a radiologist and in consultation with her doctor. 

• Whole breast ultrasounds (WBUS) create an image of the breast (also called a sonogram) and may be used as a supplemental screening tool after a mammogram. Ultrasounds can differentiate between fluid-filled masses (unlikely to be cancer) and solid masses, which may require further testing to ensure they are not cancer.
• Breast magnetic resonance imaging (MRI) is a noninvasive test that uses strong magnets and radio wave pulses to create an image of the breast. MRI is a sensitive test that can allow the radiologist to see lesions hidden within tissue that may be of concern more accurately than a mammogram or ultrasound. On the flip side, MRIs are often expensive.

One size does not fit all

There are many considerations when it comes to breast cancer screening and care. Having dense breasts is one of them. Knowing if you have dense breasts is important when considering screening options. You can ask your doctor if you have dense breast tissue and, if so, discuss how you should be screened for breast cancer.

Source: www.bcrf.org

Author

R Ellen Eye, MD, FACOG Rita Ellen Eye, MD is a board-certified OB/GYN physician who joined Premier OB-Gyn in 2014. Dr. Eye is originally from Potosi, Missouri, a small town near St. Louis (and she remains a loyal fan of the St. Louis Cardinals!). She graduated from her high school as Valedictorian. She attended Missouri University of Science and Technology, earning her Biological Sciences degree while graduating with Magna Cum Laude honors. She received her doctoral degree from the University of Missouri-Columbia in 2006. Dr. Eye went on to complete her residency in Obstetrics and Gynecology and was honored by being elected Chief Resident at the University of Oklahoma in Tulsa. She began her successful private practice in Texas where she lived and worked for four years before moving to Florida. She is married to husband Chet and a proud mom to a sweet daughter named Faith. Dr. Eye is board certified by the American Board of Obstetrics and Gynecology.