Breast Density: Why It Matters

Understanding 

breast density

can play a large role in your breast health. Like other important things about your body, it’s important to know what your breast density is. That allows you to better manage your breast cancer risk.

In the WebMD webinar “
Breast Density: Why It Matters,” Elizabeth Dibble, MD, explained how breast density affects your risk of breast cancer and why knowing your breast density is important. She also outlined the latest imaging options. 

Dibble is a diagnostic radiology specialist and associate professor of diagnostic imaging at the Warren Alpert Medical School of Brown University.

“You need to know your personal risk level of developing breast cancer as well as your breast density,” she says. 

“If you don’t have dense breast tissue and you aren’t at high risk of breast cancer, then mammograms are probably enough for you. But if you do have dense breast tissue and you’re at average or intermediate risk for breast cancer, that’s where you might want to think about having supplemental screening.”

Poll Questions

Dibble discussed different aspects of breast density and their possible impact on your health.  A webinar poll found 33% of viewers wanted to know more about breast cancer screenings, and which are best for different types of breast density.

Question: My biggest question about breast density is:

• 
  What breast cancer screening tests are best: 33%
• 
  How it changes with age: 25%
• 
  How it affects breast cancer risk: 19%
• 
  How to know if you have dense breasts: 12%
• 
  Whether breast density is hereditary: 11%

How Can You Determine Your Breast Density?

To find out your breast density, you need to have imaging tests. Breast density decreases as you age. About 75% of women under the age of 50 have dense breasts, while only one-third of women over age of 50 have dense breasts. 

Talk to your doctor if you don’t already know your breast density.

How Does Your Breast Density Affect Your Cancer Risk?

Dense breasts

are linked to a higher risk of breast cancer and more aggressive and larger tumors – as well as cancer that’s already spread to nearby lymph nodes at the time of diagnosis.

Mammograms are less accurate in screening dense breasts. So it’s important you know what type of density you have. If you have dense breasts, it’s important to take the extra steps to 

screen for cancer

.

In fact, many states have laws that require you to be notified about your breast density. In some areas, they inform you about the added benefit of extra screening.

In addition to regular mammograms, there are other screening tools to help when you have dense breasts:

• 
  3D mammogram (tomosynthesis)
• 
  Ultrasound
• 
  MRI
• 
  Molecular breast imaging
• 
  Contrast-enhanced mammogram

Viewer Questions

Is it possible to reduce your breast density through diet?

Can genetic risk skip a generation?

How is breast density affected by hormone therapy?

In general, it’s not possible to change your breast density through diet. Sometimes you might gain or lose weight, and that affects the tissue in your breasts. But there’s not much you can do to control your breast density. 

Your breast density tends to decrease as you get older, and especially after you go through menopause. But there are plenty of women in the postmenopausal phase of their life who have dense breast tissue – it’s very personal to you.

Your genetic risk of breast cancer doesn’t skip a generation. If your grandmother had a BRCA gene mutation, but you didn’t inherit that gene mutation, then your daughter isn’t going to have that gene mutation, unless she got it from the other side of the family. Dibble explained that more risk-related genes are being discovered all the time, so it’s a good idea to have genetic testing if you have high risk factors like a family history of early breast cancer. 

Hormone therapy can increase your breast density. 

Is it possible to be part of clinical trials about breast density?

How is artificial intelligence (AI) used in breast screenings, and how does it affect the accuracy of those screenings?

There are a couple of current clinical trials, one looking at molecular breast imaging and one looking at contrast-enhanced mammograms. Look online for information on those trials.

The “Density Matters” trial is run by the Mayo Clinic, and they have information about it on their website. The National Institutes of Health (NIH) also has the trials listed. You can find more information and contacts there.

It’s possible that if a clinical trial site near you isn’t enrolling, they may be in the future.

A hot topic in radiology is AI. The reality is, most of us in breast imaging are not really using AI yet for clinical purposes. There are a lot of AI programs out there. There are many FDA-approved artificial intelligence programs for helping radiologists interpret medical imaging in general.

But nobody is using it to replace the radiologist or expert interpretation of your mammogram. So you don’t need to worry about a machine interpreting your mammogram. 

There’s a lot of interest in this, because some AI programs seem to be as accurate or even able to add to the accuracy of a radiologist. So in the future, we may have the radiologist look at the imaging and then have a second read by AI.

If you need a diagnostic mammogram, do you need it every time you’re screened?

If MRI is better at detecting breast cancers, why still use mammograms?

Can there be different interpretations of breast density?

For a little background, we basically have two types of
mammograms
. The screening mammogram, which is a routine screening for everybody. And the diagnostic mammogram, which is when someone has some particular issue with their breast – maybe they had a recent history of breast cancer and we’re keeping a close eye on things. Or maybe they were called back for additional imaging after a screening mammogram because we want some more pictures. 

So it depends on the reason why you had a diagnostic mammogram. If you get called back for extra views from your screening mammogram and the radiologist tells you everything is completely fine, then you’d go back to regular screening mammograms. 

But if the radiologist found something that they think is almost certainly not cancer, but they want to keep an eye on it, they may ask you to come back in 6 months for a diagnostic mammogram.

An MRI doesn’t detect every single breast cancer that a mammogram does. Also, mammograms are what we have decades of data on, proving they decrease death and complications from breast cancer. 

So people are diagnosed early and at a lower stage, which means their breast cancers are more treatable and more curable, compared to if they don’t undergo a screening mammogram. We don’t have that kind of robust data for MRI screening, and certainly not in the dense breast population. It’s possible things could change in the future, though.

Deciding if you have dense breasts can be a little subjective. But there are some different software programs out there that give an objective measurement of your breast tissue. Overall, reviewing breast density is pretty standard among doctors.

Watch a replay of “

Breast Density: Why It Matters.”

Watch other

free WebMD webinars

by leading experts on a variety of health topics.