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Breast Density: Why It Matters

Breast Density: Why It Matters

Written by SMH Public Information Officer Kim Savage

Do you know how dense your breasts are? If you’re a woman age 40 or older, you should. 

Breast density — or the amount of fibrous breast tissue compared to the amount of fatty tissue — is an extremely important factor to consider when screening for breast cancer and can influence decisions you make when scheduling your annual mammogram. 

Studies show that women with dense breasts are 10 times more likely to have mammograms miss early-stage cancerous tumors.

“Mammography is still the gold standard for detecting breast cancers, and we know it saves lives,” said Steven Merandi, MD, a breast imaging specialist at Sarasota Memorial’s Breast Health Center. “But no tool is perfect, especially for women who have dense breasts.”

About half of all American women’s breasts are dense, having more glandular and connective tissue than fatty tissue. While mammography is the only way doctors can accurately assess breast density, women with dense breast tissue often need alternative or supplemental imaging for reliable breast cancer screening.

“In a mammogram, fatty tissue appears gray or black on the X-ray,” Merandi explained. “Dense tissue appears white, as do many cancers, so it actually blends in and can obscure early signs of breast cancer.”

Approximately 15 to 20 percent of breast cancers cannot be detected using traditional 2-D mammography

Unrelated to breast size or firmness, breast density is classified on a scale of 1 to 4, from almost entirely fatty (Level 1) to extremely dense (Level 4). And although it is loosely associated with age — nearly 75 percent of women in their 30s have dense breast tissue — more than 25 percent of women in their 70s also have dense breast tissue.

Sarasota Memorial radiologists document breast density in every mammography report and encourage a woman’s referring physician to discuss additional screenings if indicated — such as ultrasound and breast MRI, which can detect tumors that mammograms can’t see — for patients with significant breast density.

While these more sensitive screenings can detect a multitude of irregularities, the downside is that they are not as good at showing whether lesions are malignant or benign, Merandi said. That can result in unnecessary follow-up tests, biopsies and false alarms. 

“There are limitations and ramifications associated with more sensitive screenings, so often it can be a balancing act,” Merandi explained. “It’s really not a decision women should make without first talking to their doctor.”

Scheduling a Mammogram


Women age 40 or older should have a screening mammogram each year. Once you’ve talked to your doctor about the best breast imaging for you, your doctor will order the screening.

If you don’t have a primary care doctor or gynecologist, reach out to Sarasota Memorial’s HealthLine physician referral team for assistance (941-917-7777); call the Breast Health Center at 941-917-7322; or visit for more information.

Women who are uninsured or cannot afford a mammogram, breast biopsy or other breast health service should call our Breast Health Grant Support Program for assistance: 941-917-7642.

Cancer Screening for Dense Breasts

Women with dense breasts may benefit from the following imaging technologies as supplements or alternatives to screening mammograms:

Tomosysnthesis (3-D Mammography) — Younger women with dense breasts benefit the most from tomosynthesis, which provides 3-dimensional images of the breast using a technology similar to CT scans. The imaging machine moves around the breast in an arc, taking multiple X-rays that a computer forms into a 3-D image. This allows radiologists to assess several layers of the breast at a time and to navigate around tissue that might hide a cancer. It’s important to discuss this option with your doctor as it involves more radiation than a standard mammogram; and we recommend confirming with your healthcare insurer that the cost would be covered by your benefits plan.

Breast Ultrasound — For patients with dense breasts who are at lower risk for developing breast cancer, ultrasound is often the preferred follow-up to a mammogram. Ultrasound uses high-frequency sound waves and a computer to create images that help diagnose breast abnormalities, such as a benign fluid-filled cyst or a solid lump. It can be used to supplement mammography for a woman with dense breasts, but it’s not typically used as a screening tool or in place of mammography, as calcifications (which can be an early sign of cancer) cannot be well visualized using ultrasound. It also can give false positive readings; so again, it’s important to discuss this option with your doctor.

Breast MRI — Often recommended for women who have had breast cancer before, a family history of breast cancer or those who would benefit from a higher sensitivity, lower radiation screening, magnetic resonance imaging (MRI) may reveal additional breast cancers obscured on both mammography and ultrasound screening. MRI uses a combination of a large magnet, radiofrequencies and a computer to produce detailed images of breast tissue. MRI does not use radiation, but usually requires the use of a contrast dye to help create clearer images and outline abnormalities. It can also help detect breast cancer in women with breast implants and in younger women with dense breast tissue.

Get Screened: When & Where

When: Breast oncology experts at Sarasota Memorial’s Brian D. Jellison Cancer Institute advise all women to have a breast cancer screening annually starting at age 40, in addition to an annual clinical breast exam. Women should talk to their primary care physicians or gynecologist about the various screening mammography options to decide which one is the best fit, given their individual risk level, health history, breast density and other factors.

Where: To ensure reliable imaging and results, women should choose a mammography center that is an American College of Radiology “Gold Standard” Breast Imaging Center of Excellence and that offers digital mammography. Women with dense breasts or other risk factors may need 3-D digital mammography or other advanced diagnostic capabilities such as ultrasound and breast MRI.

Named a Breast Imaging Center of Excellence by ACR, Sarasota Memorial offers digital mammography, 3D mammograms and other advanced breast imaging options at 7 locations across Sarasota County. For information on screening locations and services, call Sarasota Memorial’s Breast Health Center at 941-917-4103 or click here.


Kim Savage is Sarasota Memorial's public information officer, whose duties include overseeing media relations and external communications for the health system.

Posted: Oct 20, 2020,
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Author: Ann Key