GREAT BAY--A woman goes for a mammogram and later receives a report telling her she has “dense breasts.” For many women, the term can be confusing and even alarming.
Having dense breasts is common. It does not mean that something is wrong, and it does not mean that a woman has breast cancer. But breast density matters for two important reasons: it can make some cancers harder to see on a mammogram, and women with dense breasts have a higher risk of developing breast cancer compared with women whose breasts contain more fatty tissue.
As part of The Peoples’ Tribune Breast Cancer Awareness Series, understanding breast density can help women have better conversations with their healthcare providers about their individual risk and screening needs.
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What Are Dense Breasts?
Breasts are made up of fatty tissue, glands, ducts and supportive tissue.
Breast density describes the amount of fibrous and glandular tissue compared with fatty tissue. A breast with more fibrous and glandular tissue is considered denser.
Density cannot reliably be determined by looking at or feeling the breasts. A woman with large breasts can have low breast density, while a woman with small breasts can have very dense tissue. Breast density is determined from a mammogram.
Radiologists generally classify breast density into four categories.
The first category consists mostly of fatty tissue. The second contains scattered areas of dense tissue. The third is described as heterogeneously dense, meaning there are substantial areas of dense tissue. The fourth is extremely dense.
Women in the third and fourth categories are generally considered to have dense breasts.
Why Does Density Make Mammograms More Difficult to Read?
On a mammogram, fatty tissue appears relatively dark, while dense breast tissue appears white.
The difficulty is that many breast cancers also appear white on a mammogram.
This means dense tissue can sometimes hide or “mask” an abnormality, making it more difficult for a radiologist to identify a cancer surrounded by similar-looking tissue.
Think of it as trying to find a white object against a white background. It may still be visible, but detecting it can be more challenging.
This does not mean mammograms are useless for women with dense breasts. Mammography remains an important screening tool and can detect findings, including certain calcifications, that may not be found through other methods.
Dense Breasts and Cancer Risk
Breast density is not only an imaging issue. It is also considered a breast cancer risk factor.
Women with very dense breasts have a greater risk of developing breast cancer than women with mostly fatty breasts. Scientists continue to study exactly why breast density is connected to increased risk.
Density is only one part of a woman's overall risk profile. Age, family history, genetic changes, previous breast biopsies, reproductive history and other health factors can also influence risk.
This is why breast density should be considered alongside the woman's complete medical and family history rather than viewed by itself.
Do Dense Breasts Mean You Need More Tests?
Not necessarily.
Some women with dense breasts may benefit from additional screening, such as breast ultrasound or magnetic resonance imaging, commonly called MRI. But additional testing is not automatically recommended for every woman with dense breasts.
Supplemental tests can sometimes detect cancers that are difficult to see on a mammogram, but they can also find areas that ultimately turn out not to be cancer. This may lead to additional imaging, biopsies and anxiety.
The decision should therefore be based on a woman's breast density together with her other risk factors.
A woman with dense breasts and a strong family history of breast cancer, for example, may have different screening needs from a woman with dense breasts but no additional major risk factors.
Can Breast Density Change?
Yes.
Breast density can change over a woman's lifetime. Younger women are more likely to have dense breast tissue, and density often decreases with age, particularly after menopause.
Hormonal factors, certain medications and changes in body composition can also affect breast density.
That means a woman's breast density classification may not necessarily remain the same forever.
Ask the Question
Women who are told they have dense breasts should not panic, but they should not ignore the information either.
Ask your healthcare provider what your breast density means for your personal risk. Discuss your family history. Ask whether your current mammography schedule is appropriate and whether any additional screening should be considered.
For this installment of The Peoples’ Tribune Breast Cancer Awareness Series, the message is clear: dense breasts are common, but knowing that you have them is important information.
It allows you and your healthcare provider to look at the bigger picture, understand your individual risk and decide which screening approach is right for you.
