In the latest installment of our conversations with Fort Worth newsmakers, Dr. Cynara Coomer, a breast surgeon with Texas Health Breast Specialists, discusses how breast density can affect a person’s mammogram. 

This conversation has been edited for length and clarity. For a longer version, please listen to the audio file attached to this article.

Alexis Allison: So, Dr. Coomer, the FDA recently announced new mammogram standards to support people with dense breasts. And first, I’m wondering: What does it mean if your breasts are dense?

Dr. Cynara Coomer: So breast density is about the ratio of fibroglandular tissue and fatty tissue in your breast. Fibroglandular tissue is a combination of the working parts of our breast tissue: the milk ducts and the milk sacs, as well as the fibrous connective tissue in between that. Milk is produced inside the milk sac, and then it travels down through the milk ducts, which are like little tubes that carry the milk to the nipple. 

And when we go through menopause, a lot of that tissue may atrophy. But what holds that tissue together is this fibrous connective tissue. So that gives our breasts that kind of firmer feeling and that harder portion of our breast tissue, and then the fatty tissue is really what gives our breast the size and the shape. 

The breast density in your mammogram reports is really the amount of that fibroglandular breast tissue compared to the fatty tissue. So some women, especially in our younger years, tend to have more dense breast tissue and more of that fibroglandular tissue. Over time, that may atrophy and get replaced with more fatty tissue. But for some women, they’ll have more of it throughout their life, and they may continue to have more more of it, even when they’re postmenopausal.

Allison: Can we tell if we have more dense breasts?

Coomer: If you have more dense breast tissue, your breast tissue is going to feel more firm. It’s going to feel harder than fatty tissue — fatty tissue tends to feel softer. Women who have a lower body mass index, thinner women, tend to have more dense breast tissue. And so their breasts tend to look sometimes a little bit perkier than women who are larger-breasted or have a higher body mass index. 

But the key component is really from your mammogram. So that’s really when we get to figure out how much of your breast tissue is dense. There are four categories:

  1. The first category is almost entirely fatty breast tissue. Those patients, their mammogram has hardly any fibroglandular tissue. It’s very easy to read their mammograms. 
  2. The second category is scattered fibroglandular densities, meaning there’s mostly fatty breast tissue, but a scattering of fibroglandular breast tissue or dense tissue in the breast. 
  3. The third category is heterogeneously dense, which means it’s a pretty even amount of dense breasts versus fatty tissue in the breast, sort of equal amounts. 
  4. And the last category is extremely dense, meaning that there’s very little fatty tissue, if any, and it’s just this more dense fibroglandular tissue. 

If, as a physician, I’m reading your mammogram report (and) it says ‘heterogeneously dense,’ then I know that your breast tissue is about 50% dense breast tissue. If it’s extremely dense, then I know that there’s very little fatty tissue and your mammogram is going to be a little bit harder for us to interpret.

Allison: I’m glad you brought up that last point, because I’m wondering why it matters if a person has more dense or less dense breasts.

Coomer: So it matters for two reasons. One is reading the mammograms. Women who have dense breast tissue, reading your mammogram (is) a little bit more difficult. The results are somewhat limited. 

It’s still the best screening tool, even if you do have extremely dense breast tissue, but fibroglandular tissue on your mammogram shows up as white tissue or white on your mammogram. Fatty tissue is almost black on the mammogram. Breast masses, whether they’re benign or whether they’re cancer, tend to show up as white as well. So if you have a breast mass that’s in the middle of the dense fibroglandular tissue, it may be harder for the radiologist to identify it, especially if it’s a small mass. If it’s in the fatty part of your breast tissue, then you’re going to see this white spot amongst all the black tissue, and then that’s going to be easier for them to pick it up. 

The second reason why it’s important is that women with dense breast tissue have been found to have a slightly increased risk for breast cancer. It’s not as big as other risk factors, but it does put you at a slightly increased risk.

Allison: So if you have higher density, you’re slightly more likely to have breast cancer, and it’s slightly harder for a radiologist to see that breast cancer.

Coomer: Exactly.

Allison: It’s my understanding that these new standards would require doctors nationwide to tell a patient how dense their breasts are. But Texas already has that law in place. Can you tell us a little bit about that?

Coomer: Right. Texas is one of 38 states that are currently reporting dense breast tissue on their mammogram reports. In Texas, that was instituted in September 2011. It’s called Henda’s Law. What it means is that, at the end of the mammogram report or letter — the letter that’s sent to the patient — at the bottom of the letter, if at least 50% of your breast tissue is dense, then they will put a disclaimer at the bottom of the of the mammogram report and it would say something like this: 

‘Your mammogram shows that your breast tissue is dense. Dense breast tissue is common and is not abnormal. However, dense breast tissue can make it harder to evaluate the results of your mammogram, and may also be associated with an increased risk of breast cancer.’ 

And then it goes on to advise the patient to discuss the results with their physician to determine if additional imaging would be warranted. 

Allison: What would additional screening look like?

Coomer: There are two other options that are most commonly used. One is a breast MRI. A breast MRI is somewhat invasive, meaning that it does require that an IV be placed. The MRIs are very, very good at being able to see through that dense breast tissue. 

They’re almost a little bit too sensitive. The downside is that it has a higher false positive rate than mammograms. So what ends up happening is that the patients end up needing to have a biopsy that perhaps they don’t really need. So MRIs are a great screening tool for our high risk patients — patients that have a higher than 20% chance of getting breast cancer in their lifetime. It’s a great tool for those patients to add to their screening.

It’s not always an ideal solution for patients who have dense breast tissue. Because of the higher false positive rate, insurances typically won’t pay for it for a patient that’s not high risk and it is costly. We prefer not to do it for the general population, even though they may have dense breast tissue. 

The other alternative is to do an ultrasound. Ultrasounds are typically best used as targeted screening tools, so if we’re finding an abnormality on your mammogram, then we hone in on that with the ultrasound to see if it’s a cyst or a mass and to determine if a biopsy is warranted. 

For my patients, if they have extremely dense breast tissue, and we’re not able to see much on their mammograms, then I may recommend adding the ultrasound as a screening tool. It really hasn’t been shown to pick up a whole lot more cancers. But the goal, obviously, is that if we do find something, we’re hoping to find it as early as possible.

Allison: So if there are listeners who think they might have higher density breast tissue, what would you recommend that they do with this information?

Coomer: So I would definitely discuss it with your physician. This disclaimer that we’re putting on the mammogram report, unfortunately, it can produce a lot of anxiety for patients, because now they feel like their mammogram is not really worth anything. And then, in addition to that, they feel even more concerned when they’re being told that they’re at an increased risk for breast cancer. 

In regards to the increased risk of breast cancer, again, it’s a slight increase in risk. It’s not one of the biggest risk factors. 

Your physician will be able to do a risk assessment on you to determine if you are high risk. In regards to the additional testing, mammograms are still the best screening tool for patients, even patients who have dense breast tissue. I would still just stick with a mammogram screening if you’re not a high risk patient. You could discuss with your physician whether or not they feel there’s a need to add the ultrasounds based on the amount of density in the breast tissue.

Alexis Allison: Thank you so much for talking with us today. Is there anything else that you’d like to add?

Coomer: Don’t let it make you feel more anxious and don’t feel discouraged if they do tell you you have dense breast tissue. Mammograms are life-saving. They are our best screening tool for breast cancer. And although they can’t prevent it, early detection is key and they are the key component to detecting cancer early so that a woman may have the best possible outcome.

Alexis Allison is the health reporter at the Fort Worth Report. Her position is supported by a grant from Texas Health Resources. Contact her at alexis.allison@fortworthreport.org or via Twitter. At the Fort Worth Report, news decisions are made independently of our board members and financial supporters. Read more about our editorial independence policy here.

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Alexis Allison

Alexis Allison covers health for the Fort Worth Report. When she can, she'll slip in an illustration or two. Allison is a former high school English teacher and hopes her journalism is likewise educational....