Can I get breast cancer if I have dense breasts?

Breast cancer is the most diagnosed cancer among women in the United States. In fact, it accounts for 1 in 3 new cancers in women each year.

What's more, women with dense breast tissue have a higher risk of breast cancer than women with less dense breasts. However, researchers are still investigating why having dense breasts increases the risk.

Understanding breast density

Breast density refers to the amount of fibrous and glandular breast tissue seen on mammograms compared to the amount of fatty breast tissue seen. Dense breasts are common, with mammograms classifying about 40% to 50% of women as having dense breasts.

“Dense breasts have a lot of glandular tissue — which includes the milk glands and ducts — and fibrous tissue,” says Dr. Lori Uyeno, a Sharp Community Medical Group breast surgeon affiliated with Sharp Memorial Hospital and Sharp Mary Birch Hospital for Women & Newborns. “There’s not as much fatty tissue in dense breasts.”

Breast density is most often determined by mammogram imaging, not based on the way the breast feels or looks.

Dense breast tissue and cancer diagnoses

Dense breast tissue on mammograms can mask or hide small cancers. The tissue appears white, while fatty tissue appears dark on mammograms. Irregular lumps or masses that may be breast cancer also appear white on mammograms, which can make detection difficult. “Yet, routine screening mammograms are still one of the best imaging options for detecting cancers, even in dense breasts,” says Dr. Uyeno.

Medical professional may recommend additional imaging, such as tomosynthesis or 3D mammography, when screening for breast cancer. This exam takes image in an arc to create a 3D model of the breast for a more accurate reading.

“Other types of exams include ultrasounds or breast MRIs, which may be recommended for extremely dense breast tissue,” says Dr. Uyeno.

How age affects breast density

Breast density decreases with age due to a decline in hormone levels. As a result, older women typically have less dense breast tissue than younger women. However, women who receive hormone replacement therapy (HRT) for menopausal symptoms are more likely to have high breast density compared to women who are not receiving HRT.

“Hormone replacement therapy can be effective in relieving menopausal symptoms,” says Dr. Uyeno. “It’s important for women to discuss their personal risk of developing breast cancer with their doctor before starting or continuing the therapy.”

Additionally, it's essential, she says, for women to be vigilant in monitoring their breast health.

“Look out for any changes in the appearance or feel of the skin and breast, including the nipple, and talk with your doctor if you have concerns," Dr. Uyeno advises.

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