Does Breast Density Really Matter?

The Silence Around Breast Density

Having dense breasts isn’t rare — in fact, around 50% of women do. Yet for years, it wasn’t something most of us were ever told about, or even encouraged to ask about. My own doctor never mentioned it to me, despite the fact I’d been having annual mammograms for more than 15 years. If it matters so much, why is no one talking about it?

And here’s a crucial point: you can’t tell if you have dense breasts by touch or feel. Density can only be seen on a mammogram.

That silence is finally starting to shift. In the US, a new federal mandate now requires that all women undergoing a mammogram be informed of their breast density. Unfortunately, in the UK, it is still not mandatory for breast density to be included on a woman’s mammogram report — leaving many women unaware of a factor that could directly affect both their screening and their risk.

Why Breast Density Matters

I’ve since learned that I have extremely dense breasts — and yes, that is an official medical classification. At first, I had no idea what this meant, but I quickly discovered two big reasons why every woman should know her density:

1. It makes mammograms harder to read.
On a mammogram, dense tissue appears white — the same colour as cancer. For radiologists, it can be like searching for a snowflake in a snowstorm. Dense breasts don’t mean cancer is there, but they do make it harder to spot if it is.

“Dense breasts don’t mean cancer is there — but they do make it harder to spot if it is.”

So what happens if your mammogram doesn’t show much? You might be sent for an MRI, which can pick up things a mammogram misses. But don’t relax just yet — MRIs have their own blind spots. They might highlight something suspicious, but they don’t show calcifications, which can be an early sign of breast cancer. That’s why, even if you have dense breasts, you often need both a mammogram and an MRI — or another screening tool such as an ultrasound — for the fullest picture.

And then there’s the practical question: will your insurance pay for that extra MRI? In some places, yes — especially if you’re considered high risk. In others, you may be told it’s “not necessary” and be left to fight for coverage, or to pay out of pocket. Like so many aspects of women’s health, access can come down to where you live, what your insurance allows, and how hard you’re willing (or able) to push.

2. It increases breast cancer risk.
This was the part I hadn’t realised. Dense breast tissue itself is an independent risk factor for breast cancer. To complicate matters further, HRT can increase breast density in some, though not all, women — and when HRT is stopped, density generally returns to its previous state. Combined HRT in particular is known to add to the density issue, amplifying the already heightened risk that comes with having dense breasts — and making cancers even harder to see on mammograms. Healthcare providers often weigh this as part of the risk–benefit assessment when discussing hormone therapy with women.

And yet, here’s the conundrum: I am a supporter of HRT. For me, it has been life changing. I had dense breasts before I ever started HRT, and I still have dense breasts now. HRT didn’t cause the density in my case — but it remains part of the complicated balance women face when making decisions about health.

How Breast Density Is Classified

Breast density is measured in four categories:

A: Almost entirely fatty
B: Scattered areas of fibroglandular density
C: Heterogeneously dense
D: Extremely dense

Half of all women fall into categories C or D — meaning that dense breasts are not unusual, but they are significant.

My Reflection

For me, discovering I was classified as “extremely dense” (category D) changed the way I think about both my screenings and my risk. In Singapore, it was standard for me to have an ultrasound alongside my mammogram, but when I lived in the US, I had to fight for that extra step. Later, when I began reading about the importance of MRIs, I was floored. No one had ever explained that to me, and my doctor had never once mentioned it.

Suddenly, it made sense why I’d been sent for additional imaging in the past — and why mammograms alone don’t always give the full picture. Most of all, it left me asking: if breast density is such an important piece of the puzzle, why did no one ever tell me?

That question still stays with me. Does breast density really matter? The research says yes. It affects how accurately cancers are picked up on a mammogram, and it is considered an independent risk factor for developing breast cancer. But it’s also important to note that having dense breasts does not increase the risk of dying from breast cancer.

Until doctors start routinely sharing this information, many women will continue to live in the dark — not knowing, not asking, and not realising how much it might mean.

Resources & Further Reading

📄 Websites & Guidelines
- DenseBreast-info.org — patient-friendly education on dense breasts and screening
- Breast Cancer Now – Breast Density
- Dense Breasts Canada — advocacy and education on breast density and screening
- U.S. FDA Mammography Reporting Requirements — new federal mandate on breast density reporting
- The Guardian: ‘My cancer was not in those pictures’: how breast density affects mammograms (10 Oct 2024) — a powerful real-life account combined with medical insight on breast density and screening limits
🎧 Podcasts & Multimedia
- Menopause Chicks Podcast — Season 1, Episode 5 (Oct 1, 2023): “It’s About Breast Density with Jennie Dale”
  A thoughtful discussion on breast density, disparities in screening access, supplemental imaging like ultrasound vs MRI, and advocacy efforts in Canada.

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