Do You Have Dense Breasts? (And Why You Need to Know!)

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**** I am not a medical professional. This is for information only. Please talk to your own doctor for personalised advice ****

Twelve months ago I had no idea that dense breasts were a thing. I mean, breasts are breasts right? But no, apparently not all breasts are created equal, and I wish I had known earlier about dense breasts and what it could mean when it comes to breast cancer.

But what are dense breasts? Basically it means breasts that have a higher ratio of fibrous tissue to fatty tissue. Almost everyone has denser breasts when they are young, and as we get older they generally – but not always – become less dense. But at the same time, if we have denser breasts than others in our age bracket at a young age then we will likely still have denser breasts then others in our age bracket at an older age.

The problem is there is no way to tell if we have dense breasts just by looking at them. It has nothing to do with size nor shape nor firmness. The only way to find out is through mammogram.

But here in Australia we don’t tend to start getting mammograms until we are 50 – because that’s when the government starts to remind us to get screened. (It should be noted screening is free from 40 in Australia, but many people do not realise this so don’t get tested until 50)

The issue is, when we have that first mammogram, it’s unlikely that there will be any mention of breast density. Your GP probably won’t mention it to you, and it’s unlikely to be in your mammogram results. At least not clearly written.

I only discovered that my breasts were dense after I was diagnosed with DCIS (Ductal Carcinoma in Situ). It was not mentioned to me by any of the doctors involved, but rather I found the information as I went through my pathology results and googled each term to make sure I understood exactly what was going on.

What I discovered was the BIRADS density scale. Breast density is rated from A-D, with A being less dense (mostly fatty tissue) and D being the most dense (mostly fibrous tissue). This one little line on my pathology report could make all the difference.

There are two reasons why, as soon as we have our first mammogram, we should learn what our BIRADS score, and therefore breast density, is.

Firstly, dense breasts make it more difficult to read a mammogram. The dense tissue appears white on a mammogram, but so does cancer, and therefore it is very difficult to tell one from the other.

Dense breast tissue is why mammograms are not often used as a tool for women under 40.

Below is my mammogram. I had 10cm of DCIS in my right breast (+ a tiny invasive ductal carcinoma) but nothing out of the ordinary appeared on my mammogram. My left breast has no cancer, but they look pretty much the same. Scary huh? If I had gone for a normal screening mammogram rather than a diagnostic one after my GP being concerned, my breast cancer would have been missed.

We trust and rely on these mammograms to find cancer early, but if you have dense breasts, this may not happen.

If you know you have dense breasts in advance, you can speak with your doctor and perhaps arrange extra screenings such as 3D mammograms, ultrasounds or MRIs. Thanks to my diagnosis and discovering her own dense breasts, my sister has been able to do just that. At the very least you will be aware of the fallibility of the screening mammograms and be on the look out for other signs too.

The second reason why it is important to know if you have dense breasts is because cancer studies have shown that you could be at a higher risk of breast cancer simply because of your dense breast tissue.

This is an excerpt from the BNCA website:

Research also shows that breast density can itself be a risk factor for developing breast cancer.

  • For the approximately 40 percent of women who have ‘heterogeneously dense breasts’ (Type C on the BI-RADS scale), the risk of developing breast cancer is thought to be 1.2 times greater than average.
  • Women with extremely dense breasts (Type D) are 2.1 times more likely than average to develop breast cancer, and up to 6 times more likely than women with mostly fatty (Type A) breasts.

Conversely, those with low breast density (Type A) have a lower risk of breast cancer than average.

So if our breast density increases our risk of breast cancer, why don’t we hear about it more often? Very good question, and I honestly don’t know the answer to it. Perhaps it’s because the BIRADS rating is given based on the opinion of the pathologist. It’s a judgement call, and people can be slightly inconsistent from time to time. Perhaps it’s because breast density can change as we age. Perhaps our doctors don’t want to give us one more thing to worry about. Whatever the answer, I think we need to spread the word – especially to our cancer-free friends and family so they know what to look for. 

We don’t need to panic if we have dense breasts, but the more information we have about our bodies, the more informed our decisions can be. As the saying goes, “forewarned is forearmed”. Look out for your BIRADS density score on your latest mammogram report.

I hope by writing this blog post I can at least spread a little more awareness about breast density and why knowing it could help you detect breast cancer earlier. And we all know that early detection is the best way to beat breast cancer. Absolutely still get those regular mammograms, just know there are limitations too.

To read more about breast density, I recommend taking a look at the following links:
Mammographic Density and Screening (Breast Cancer Network Australia)
Breast Density and Your Mammogram Report (American Cancer Society)

Please share this with all your friends, especially ones without breast cancer so they can learn about dense breasts.

Want to read more about my breast cancer journey? Try these posts


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  1. Thank you for raising the awareness of dense breast tissue. I was told since I was in my thirties that my breasts were dense. Fast forward 20+ years, a screening mammogram showed no pathology, but a MRI was recommended due to a high risk score. Well, guess what? The MRI detected invasive lobular carcinoma. Fortunately, it was caught very early with no lymph node involvement. Please pay attention to those scores and ask if you are not told. I was blessed to have such early detection, as I did not have to go through chemo or radiation.

    1. So glad you knew what to look for!I can’t believe it’s not something we are made aware of earlier – or at least told it’s a thing to look out for.

  2. Julie, I was the same, mammogram 21 was clear. Ultrasound 22 was clear ( but lymph node was up, was asked if I had had Covid recently, yes, 2 weeks ago… ah that’s why your lymph node is up ) fast forward 6 months and my left breasts changed shape. Initially stage2 invasive lobular cancer. 3 days before my double mastectomy – stage 4 it’s in my bones… operation cancelled, drugs for life. I knew my breasts were dense, but no one told me what that meant….. I now know 🙁

  3. Josie,
    Thank you so much for sharing your BC journey! I was diagnosed with Invasive Ductal Carcinoma after my biopsy from a self discovered lump in my left breast at the 11:00 position.I’ve always known that I had dense breasts but it wasn’t until this year that I found out there was a rating for it and that regularly mammograms were not sufficient testing.I’ve had a sentimental lobe biopsy and thankful I am node0 for cancer.I just finished my 3rd of 4 chemo treatments to shrink my very large tumor before surgery. Chemo is working.I can no longer feel my tumor. With my chemo nearly over I have met with my plastic surgeon and have started researching mastectomy surgeries and I have to say your blog is the absolute best I’ve come across in my many many hours of research..It was very brave of you to share this along with the photos which were fantastic and reading this has eased my mind about my upcoming surgeries. The links you provided are great. I’m so happy you included breast density.The Tamoxifen blog was very informative as I also was ER/PR + and dreading having to take medication for the next 5 years and worrying about side effects. Thanks again. I can only imagine how many women you have helped by sharing your very personal story.

    1. Thank you so much for your kind words Rebecca. I get as much out of helping others as they do from reading my story. I absolutely believe we need to share more of our journeys to make it less scary for those who follow us. Take car and good luck with your treatment.

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