What Does “heterogeneously Dense Breast Tissue” Mean?

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Heterogeneously dense breasts is a term used in mammography to describe breasts with a higher percentage of glandular and supportive tissue than fat. It occurs in 40% of women and while normal, can make it more difficult to detect breast cancer on mammography. Dr. Margaret Polaneczky explains that, under this classification, the breast composition measures between 51 – 75 percent glandular.

When a mammography is performed, breast cancers appear white on the mammogram, while fat appears dark. The difficulty is that glandular tissue, the part of your breast that makes milk, also appears white, making it more difficult to detect cancer. Breast density is a leading reason why mammography screenings fail to detect cancer in young and older women.

Unfortunately, women with heterogeneously dense breasts run the risk of having their breast cancer missed during the early stages of development. When the cancer is detected, it is often in the latter stages and requires invasive treatments with poorer prognosis for survival. Additionally there is evidence that some women with dense breasts may have a higher-than-average risk of breast cancer.

Twenty-one states have breast density notification laws that require women to be informed about their breast density levels after a mammogram procedure. They are also advised to speak with their doctor about further screening tests. It is recommended that any woman undergoing a mammogram request a copy of her report, and contact her doctor’s office with any questions.