The Importance of Informing Women About Dense Breast Tissue

Across the country, more and more women will be informed when mammography reveals dense breast tissue – and that’s a good thing.

Rhode Island recently joined California and 16 other states with the passage of a breast density inform law requiring radiologists to inform women when screening mammography reveals dense breast tissue. It has been a little more than one year since California’s own breast density inform law went into effect and it is worth taking a moment to remember why it is important to make women aware if they have dense breast tissue.

A Brief History of Breast Density Legislation

Nancy Cappello, Ph.D., is a breast cancer survivor and early advocate of breast density inform laws. She had received regular screening mammograms for about a decade and none revealed cancer. Radiologists noted in Dr. Cappello’s mammogram reports that she had dense breast tissue, but none declared that her dense breast tissue might make mammography less reliable.

When Dr. Cappello’s physician detected a ridge during a physical examination, he ordered a mammogram and a breast ultrasound on the same day. The mammogram returned no signs of cancer, but the ultrasound detected a tumor the size of a quarter. Dr. Cappello was diagnosed with breast cancer, which had spread to her lymph nodes.

We can only imagine Dr. Cappello’s frustration when she learned that dense breast tissue can reduce mammographic accuracy. “Why don’t you routinely tell women this?” she asked her gynecologist, according to a 2012 Wall Street Journal article.

Thanks in large part to the efforts of Dr. Cappello, and women like her, physicians in 17 states are now legally required to tell women when mammography reveals dense breast tissue. This should be routine everywhere. Approximately 50 percent of all women have dense breast tissue and 20 percent of these women have extremely dense breast tissue. These women have a right to know how breast density affects their breast screening and how they can use that knowledge to decide if supplemental screening is appropriate.

Why does breast density matter?

If we think about breast cancer at all, then we need to think about breast density. There are two primary reasons:

• Dense breast tissue can mask cancer in mammographic images, causing the cancer to go undetected;
• Women with dense breast tissue have a greater risk for developing cancer than women with fattier breast tissue.

Over the past decade and beyond, research has determined that mammographic accuracy is reduced in women with dense breast tissue and that dense breast tissue can increase a woman’s risk for developing breast cancer.

Researchers from the Campbell Family Institute for Cancer Research in Toronto collected breast screening data on 1,112 patients to investigate the relationship between breast density and breast cancer risk. According to results published January 2007 in New England Journal of Medicine, they found that women whose mammograms revealed density in more than 75 percent of their breasts were approximately 4.5 times more likely to be diagnosed with cancer than women whose mammograms revealed density in less than 10 percent of their breasts.

In another study of more than 2,000 women with dense breasts and other high risk factors, 111 breast cancers were detected. Mammography by itself detected 33 cancers, ultrasound by itself detected 32, ultrasound and mammography used together detected 26 and MRI used by itself detected 9, according to results published April 2012 in Journal of the American Medical Association. In other words, in women with dense breasts, extremely dense breast tissue and other high risk factors, screening mammography missed approximately one-third of breast cancers.

What can women with dense breasts do?

Women with dense breasts have options at their disposal to ensure that, if they develop cancer, it is diagnosed as early as possible to ensure best possible chances for treatment. Supplemental breast cancer screening procedures for women with dense breast tissue include:

• Breast MRI, one of the most accurate breast cancer imaging procedures available, is recommended by the American Cancer Society as a supplemental breast cancer procedure for women with a 20 percent or greater lifetime risk for developing breast cancer and it is also appropriate as supplemental breast cancer screening in women with dense breast tissue.
• Breast ultrasound, and automated breast ultrasound (ABUS), can be used in combination with screening mammography in women with dense breast tissue to help detect breast cancers masked by dense breast tissue.
• 3D mammography, also known as breast tomosynthesis, is not technically a supplemental procedure, but a relatively new and improved mammography technology, which can be used as an alternative to traditional mammography and may be especially helpful in detecting breast cancers in women with dense breast tissue.

In California, if mammography reveals dense breast tissue, you will receive a notice that reads:

“This information about the results of your mammogram is given to you to raise your awareness and to inform your conversations with your doctor. Together, you can decide which screening options are right for you.”

At Breastlink, we strongly advise women with dense breasts take this advice. Talk to your physician about supplemental breast screening procedures, such as ultrasound or MRI. Ask the facility where you receive screening mammography if they perform supplemental breast screening exams as well. While annual mammograms starting at age 40 is still recommended regardless of breast density, supplemental screening may be appropriate for you.

The bottom line is that we do not recommend screening mammography alone in women with dense breasts and extremely dense breast tissue, and we need to work harder to make them aware of what’s out there.