Breast Density – Why it Matters
The following Q&A explains what breast density means and why mammography alone is not always enough when screening for breast cancer.
Q. I had a mammography recently and was told that I have dense breast tissue. What does that mean?
A. Breasts are made up of fat and non-fatty glandular and connective breast tissue. Some women have more fat than breast tissue, while others have more breast tissue than fat. Breasts that have higher proportion of the glandular tissue are described as “dense.”
Q. Is it unusual to have dense breasts?
A. Every woman’s breasts are different. Some are fatty, some are dense, and some are a mix. Approximately 46 percent of American women have dense breasts.
Q. My breasts don’t feel dense, so I must not have dense breast tissue, right?
A. Breast density is not evident by feel or appearance. The only way to determine whether breasts have dense tissue is by evaluating a mammogram.
Q. Who determines whether or not I have dense breasts?
A. The radiologist who looks at your mammogram classifies breast composition into one of four categories
of increasing density: predominantly fatty, scattered fibroglandular tissue, heterogeneously dense or extremely dense.
Q. Will I always have dense breasts?
A. Dense breast tissue is a physical attribute like other features of your body. You cannot actively modify density, but it can change as a result of age, hormone levels and menopause. As women age, their breasts may become less dense. Extremely dense or heterogeneously dense tissue is present in more than half of women under age 50 and in only one-third of women age 50 or older.
Q. Why does it matter if my breasts are dense?
A. Regardless of size or shape, women who have dense breasts have a greater risk of developing breast cancer than women with fatty breasts. Dense tissue may also obscure underlying abnormality, making it harder to detect early cancer.
Q. How can women be sure they will be told if they have dense breasts?
A. Recognizing the importance of early detection of breast cancer and the fact that women with dense breasts have a higher risk for developing it, several states – including New York – have passed legislation requiring mammography services to inform patients if dense breast tissue is seen during an exam. The intent of the law is to empower women to discuss additional screening options with their physicians.
Q. Will a tumor show up in a mammogram of a dense breast?
A. Looking for a tumor in mammography of dense breasts is like looking for a snowball in a snowstorm, because dense breast tissue looks white on the mammogram and masses or lumps also appear white. That’s why a cancer can easily hide in a background of dense tissue. Conversely, fatty breasts show up mostly black and grayish on a mammogram, so detection of a suspicious mass is more sensitive.
Q. Is there another test that can detect cancer in dense breasts?
A. Ultrasound can help identify masses that are hard to see on a mammogram. MRI is a useful tool as well. The Avon/ACRIN 6666 study showed that among women who were at risk for developing breast cancer and had dense breasts, ultrasound as an adjunct to a screening mammogram increased detection by revealing certain cancers that do not show up in mammography.
Q. What is ultrasound?
A. Ultrasound is a non-invasive method that uses high-frequency sound waves to look inside the body and create a detailed image of an organ or tissue.
Q. Should I skip having a mammography and just go for an ultrasound screening?
A. No. Mammograms are still being used as the primary imaging method of breast cancer screening. Mammography is the most sensitive modality to detect calcifications (deposits of calcium that can be seen on a mammogram) that are sometimes produced by early breast cancers. Also, comparing a mammogram with a previous year’s exam allows small changes to be seen. If you have dense breasts, having both a mammography and an ultrasound screening will provide a more complete evaluation. Screening breast MRI is another effective supplemental modality for breast cancer detection.
New 3-D Ultrasound System Now at Phelps
To provide women with the benefits of the latest state-of-the-art ultrasound screening technology, Phelps Memorial Hospital Center recently became the first hospital in the Hudson Valley Region to acquire the G.E. Invenia™ Automated Breast Ultrasound System (ABUS), which is FDA-approved as a supplemental screening modality for cancer detection in women with dense breast tissue.
Like traditional breast ultrasound, ABUS also uses ultrasound technology to generate images. The difference is that the data generated with ABUS is in a 3-D format, allowing more ways for the radiologist to analyze the images. ABUS also allows for a more uniform way of acquiring the images by being less operator-dependent, since the technologist does not have to manually guide an ultrasound wand. Studies have shown that the cancer detection rate is higher among patients with dense mammograms when mammography is combined with a supplemental screening modality such as ABUS, traditional breast ultrasound or breast MRI.
The Breast Imaging Center at Phelps Memorial Hospital has been designated a Breast Imaging Center of Excellence by the American College of Radiology (ACR) for many years.