Dense Breasts and Your Mammogram: What Hamilton Women Should Know About Breast Density

By Kamandeep Chhabra, CCPA, MRT(N) — Director of Operations & Physician Relations, Limeworth X-Ray & Ultrasound, Hamilton

If your last mammogram letter mentioned that you have dense breasts and you weren’t quite sure what to make of it, you’re not alone. It’s one of the things patients ask us about most, usually with a bit of worry in their voice. So let me explain what it actually means — because in most cases it’s far less alarming than it sounds.

First, What "Breast Density" Really Means

Breast density has nothing to do with how your breasts feel, or how big or firm they are. It’s simply what your breast tissue looks like on a mammogram — how much of it is glandular and fibrous tissue (which shows up white) versus fatty tissue (which shows up dark).

You can’t tell whether you have dense breasts by touch. The only way to know is from a mammogram, where the radiologist assigns a category.

The Four Density Categories (BI-RADS)

Radiologists grade density on a scale called BI-RADS, from A to D:

• Category A — almost all fatty tissue (least dense)

• Category B — a few scattered areas of density

• Category C — fairly dense throughout

• Category D — extremely dense (the most dense)

Having dense breasts is completely normal, and it’s especially common in younger women. Density also tends to ease off as you get older.

Why It Matters

There are two reasons we pay attention to density. First, dense tissue can hide things on a mammogram — dense tissue and many tumours both show up white, so very dense breasts can make a small cancer harder to spot. We call that a "masking" effect. Second, higher density is, on its own, a modest risk factor for breast cancer.

Now, none of this means a mammogram isn’t worth doing if your breasts are dense — far from it. A mammogram is still the foundation of breast screening and your single most important test. Density just gives you and your doctor one more thing to keep in mind.

How Ontario Handles It

In the Ontario Breast Screening Program (OBSP), the radiologist reading your mammogram determines your density, and Ontario Health now tells you your BI-RADS category right in your results letter.

Back in December 2023, Ontario Health recommended publicly funding extra screening (like a breast ultrasound or MRI) for women with the densest, Category D breasts. That supplemental screening isn’t offered automatically through the OBSP yet, but your family doctor can talk it through with you and refer you for additional imaging, which OHIP covers in eligible cases. The program also keeps recalling women with Category D density for their regular screening.

Here’s my advice: keep getting your regular mammogram, and if your letter says Category C or D, take it to your family doctor and ask whether a supplemental breast ultrasound makes sense for you.

How We Can Help in Hamilton

At Limeworth, we do both digital mammography and breast ultrasound under one roof, right here on the Hamilton Mountain near CF Lime Ridge Mall. So if your doctor recommends an ultrasound because of dense breasts, we can usually get you in quickly — Saturdays included — instead of leaving you waiting weeks.

Your breast health is worth a conversation. Know your density, keep your screening on track, and let us handle the imaging part.

Frequently Asked Questions

Are dense breasts dangerous?

Not in the way people fear. Dense breasts are common and normal — not a disease. They do slightly raise your risk and can make a mammogram harder to read, which is exactly why your density gets reported to you and why it’s worth a chat with your doctor.

How do I find out my breast density?

You can’t feel it — it’s read off your mammogram by a radiologist. In Ontario, your BI-RADS density is included in the results letter you get after an OBSP screening mammogram.

If my breasts are dense, do I still need a mammogram?

Absolutely. A mammogram is still your most important screening test. Dense breasts might mean your doctor adds a supplemental ultrasound, but it never takes the place of the mammogram.

Does Limeworth do breast ultrasound for dense breasts in Hamilton?

Yes. We offer both digital mammography and ultrasound at our Hamilton Mountain clinic. If your doctor gives you a requisition for a supplemental breast ultrasound, just email it with your phone number to 849xray@gmail.com and we’ll book you in.

Book Your Mammogram in Hamilton

Limeworth X-Ray & Ultrasound is a proudly OBSP-participating, ICHSC-accredited diagnostic clinic on the Hamilton Mountain, conveniently located near CF Lime Ridge Mall with Dynacare bloodwork right across the hall. Our experienced, compassionate female mammography technologists, modern digital mammography, and fast appointments (including new Saturday availability) make breast screening easy.

To book: Email your phone number and your doctor’s requisition to 849xray@gmail.com, or call 905-574-7755. Women aged 40–74 can self-refer for an OBSP screening mammogram — no doctor’s referral needed.

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