Dense Breast Cancer Screening Should Include Automated Breast Ultrasound (ABUS)

By Jon Ekstrom, MD | RAPC

A woman with fatty breasts is less likely to develop breast cancer than a woman who has dense breasts. Also, the denser a woman’s breasts, the higher her risk of developing breast cancer. Today, women with dense breasts are having mammograms as well as additional breast cancer screening tests. One of the newest supplemental breast cancer screening tests is the revolutionary Automated Breast Ultrasound (ABUS).

Additional Cancer Screening Tests for Dense Breasts Are Beneficial

We all know that one of the best ways to detect breast cancer early on is with regularly scheduled mammograms. However, when a woman has dense breasts, the radiologist may have difficulty reading her mammogram. A radiologist is a doctor who specializes in reading medical images. This difficulty reading her mammogram makes a woman with dense breasts a good candidate for additional cancer screening tests. Doctors frequently use tests like Hand-Held Ultrasounds (HHUS) and Magnetic Resonance Imaging (MRI) to supplement mammograms. Now, an easier, faster and more comfortable test is available, the Automated Breast Ultrasound.

Understanding Dense Breast Tissue

The breasts consist of glandular tissue and ducts as well as fibrous and fatty tissue. The glandular tissue produces milk. The ducts carry milk from the glandular tissue to the nipple. Besides giving the breast its shape and size, the fatty and fibrous tissue hold the other parts in place.

Dense breast tissue has very little fat but a lot of glandular or fibrous tissue. Dense breasts are common; however, the degree of density varies. For most women, as part of the natural aging process, their breasts become less dense. Even so, there are women who experience very little change in their breast density as they age.

Determining Breast Density

There is no relation between the density of a breast and its size or firmness. For this reason, a woman cannot determine her breast density on her own. However, the radiologist reading her mammogram determines the density of her breasts and includes this information in her report.

Categorizing breast density and recognizing its prevalence:

1. Fatty Breasts – Breasts that consist almost entirely of fat tissue. About 10 percent of women have this breast density.
2. Scattered Fibroglandular – Breasts that have dense tissue in just a few areas. Around 40 percent of women have this breast density.
3. Heterogeneously Dense Breasts – Breasts with dense tissue that is evenly dispersed. This type of breast density is rather common with approximately 40 percent of women falling into this category.
4. High-density Breasts – Extremely dense breasts are somewhat rare, affecting only about 10 percent of women.

Why You Need to Know Your Breast Density

Women with dense tissue are two to four times more likely to develop breast cancer than women with fatty breasts. Also, the denser a woman’s breasts, the more difficult it becomes for the radiologist to see cancer. Dense breast tissue has always made reading mammograms more difficult for radiologists. However, the connection between dense breast tissue and breast cancer are just now becoming evident.

How Do Dense Breasts Make It Hard to Read a Mammogram?

On a mammogram, the dense breast tissue appears white, but so do tumors and breast masses. Therefore, the dense breast tissue can easily hide these growths. Since the fatty tissue looks almost black on a mammogram, white tumors and breast masses are a lot easier to find.

Should Women with Dense Breasts Still Have Mammograms?

Yes, regularly scheduled mammograms are still important. Some of the radiologists who read these tests do detect breast abnormalities, even in women with dense breasts.

Supplemental Breast Cancer Testing Options for Women with Dense Breasts

There are additional breast cancer screening tests that can be done with a mammogram. While doctors frequently use the HHUS and MRI for additional testing, the newest supplemental test for breast cancer screening is the Automated Breast Ultrasound.

Supplemental testing options include:

• The Hand-Held Ultrasound – This test takes at least 30 minutes, is dependent on the operator and difficult to reproduce. Nonetheless, this test does not require the use of radiation and is priced reasonably.

• An MRI – During this test, a machine creates detailed pictures of the inside of the body. This test is operator dependent. When a doctor orders this test to check dense breasts, the patient may receive an injection. This injection is a contrast agent (dye), which makes the tissues and blood vessels easier to see. An MRI is challenging for patients with claustrophobia because the patient lays inside a narrow tube. However, the patient may receive a sedative so she feels more comfortable. The patient lays face down and remains perfectly still throughout the exam. In addition, her breasts hang freely through a hollow depression in the table. An MRI takes from 45 minutes to an hour. This test uses no radiation; however, an MRI is more expensive than a mammogram and an ultrasound.

• The Automated Breast Ultrasound – This test is more convenient than the MRI and the HHUS. The ABUS is operator independent, does not require entering a narrow tube or taking a sedative. In addition, the patient does not receive any type of injection. This exam is reproducible and only takes about 15 minutes. In addition, the ABUS exam uses no radiation and is reasonably priced.

Study Shows the ABUS Helps Detect Cancer in Dense Breasts

The SomoInsight Study shows that the 3D ABUS is beneficial as an add-on breast screening exam for women with dense breasts.

Study results:

Using the ABUS as part of a breast cancer screening program increases detection by 1-2 cases/1,000.

The most advanced 3D Mammography Practice detects 6 cases/1,000. The ABUS and the Advanced 3D Mammography detect 8 breast cancer cases/1,000. The combination of these two procedures results in a substantial breast cancer detection increase of 33 percent.

U.S. Congress Passes National Breast Density Legislation

The link between dense breasts, breast cancer and mammogram screening has led to the development of National Breast Density (NBD) Legislation. Congress passed the NBD law on February 15, 2019. This law requires that the FDA create a reporting language to inform a patient when her breasts are dense. In addition, the patient’s referring physician is notified of her diagnosis. On March 27, 2019, the FDA proposed amendments to the Mammography Quality Standards Act (MQSA). These amendments include a proposal about notifying patients when they have dense breast tissue.

As of January 2020, 38 states have Dense Breasts Notification Laws in place. Eventually, every state may need to notify women when they have dense breasts. Even women who receive normal mammogram results need to know their breast density.

About Author:

Dr. Jon Ekstrom specializes in Women’s Imaging, Musculoskeletal and Pediatric radiology. He studied medicine at Oregon Health Sciences University in Portland. He had a fellowship at the University of Washington, specializing in MRI, CT and ultrasound. Dr. Ekstrom also completed a Pediatric Radiology residency at University of Colorado in Denver. Dr. Ekstrom joined Radiology Associates in July 1989.