Dense breasts and breast cancer risk: What to know about the link

Many women don't know that dense breasts raise the risk breast cancer, and in some states, medical providers aren't required to notify women of their breast density.

Most women are aware that a family history of breast cancer increases their risk of the disease, but far fewer understand that extremely dense breasts can pose a greater risk.

A survey published Monday in the journal JAMA Network Open found that of nearly 1,900 women who participated, the majority saw breast density as a less consequential risk factor than family history.

But women with extremely dense breasts, which are characterized by minimal fatty tissue, face a risk of breast cancer four times higher than women with the lowest breast densities, according to the study. About 10% of women who get mammograms have this level of breast density. By comparison, having a mother, sister or daughter who's had breast cancer is associated with double the risk of the disease.

Women who have a substantial amount of dense breast tissue but not to an extreme degree — about 40% of those who get mammograms — have a 20% higher risk of breast cancer relative to those with average breast density, according to the study.

That’s slightly lower than the risk associated with having a glass of wine each night, according to Dr. Phoebe Freer, chief of breast imaging at the University of Utah Department of Radiology and Imaging Sciences, who wasn't involved in the survey.

https://www.nbcnews.com/health/womens-health/dense-breasts-risk-breast-cancer-rcna67692

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