06/12/2026
You have probably seen the statistic.
“Up to 50% of women have dense breast tissue.”
It is repeated across awareness campaigns, clinical handouts, and advocacy websites — including by well-meaning organizations doing important work.
But here is what that number leaves out:
Not all density is the same. And not all density carries the same clinical implications. By collapsing four distinct, clinically meaningful categories into a single phrase, we are failing the patients who need precision the most.
———
Here is what the science actually says.
Breast density is classified into four categories:
🔵 Category A — ~10% of women
Mostly fatty tissue. Standard mammography is highly effective.
🔵 Category B — ~40% of women
Scattered fibroglandular density. Does NOT meet current recommendations for supplemental screening.
🟡 Category C — ~40% of women
Heterogeneously dense. Meets recommendations for supplemental screening. Mammograms may miss cancers.
🟡 Category D — ~10% of women
Extremely dense. Meets recommendations for supplemental screening. Significantly limits mammogram sensitivity.
The real statistic?
It is not that 50% of women have dense breasts.
It is that 50% of women — Categories C and D — meet the current guidelines recommending supplemental screening beyond a standard mammogram.
That is a very different sentence. And it matters enormously.
Imprecise language in health education is not neutral. It has consequences.
This October, we are bringing this conversation into the room where it belongs.
The Breast Density Summit | October 8, 2026
Palo Alto, CA · Wilson Sonsini Goodrich & Rosati
Join Us! Comment for the link.
🧭 Join our Advisory Board: clinicians, radiologists, researchers, patient advocates, and health communications experts.
Every woman deserves to know exactly what her results mean — and exactly what to do next.
