How to find out "mammographic density" and dense breast tissue
- Detailed cancer.org guide to breast cancer detection, including dense breast tissue” discussion.
Hints from a radiologist.
You can ask for a copy of the radiologist’s report from your last mammograms.
Sometimes the report will say whether or not the mammograms show dense breast tissue. If the report says they are "very" dense, then they are probably in 75% to 100% density category. If the report says they are "somewhat" or "moderately" dense, then they are probably in the 50% to 74% category. If the report says the breasts are " entirely fatty", they are probably in the 0% category. If the report says they are "mostly" or "somewhat" or "partially" fatty, they are probably in the 1% to 24% category. Note: Some radiologists are not required to describe the mammographic density in their reports. Many radiologists do not mention anything about mammographic density, unless the density is great enough to interfere with their ability to interpret the mammograms.
What if the mammograms were taken as part of an organized screening program?
In this case, there may not be a written radiologists report, but some screening result data must be recorded somewhere. You can ask the screening program administrators if mammographic density is recorded in their databases. Many (but not all) screening programs do this, and they may be able to tell you your mammographic density.
You can ask the radiologist
who reported the mammograms, to estimate your mammographic density percentage. You can just ask “Do I have dense breast tissue?” Some radiologists would happily do this for you. Others might be too busy or hard to reach.
You can ask to see your mammo films,
and judge for yourself. Some mammography centers will loan you your mammograms. Others may offer to charge you a fee to make copies of the films. Without taking your mammograms away from the mammography center, should at least be able to look at them for free. When you look at your mammograms you can judge the density for yourself.
See these examples of what mammograms look like
|1% to 24% density|
|25% to 49% density|
|50% to 74% density|
|75% to 100% density|
A woman’s risk of breast cancer increases if her breasts are mammographically dense. You can test this using the breast cancer risk calculator.
The chat above is highlighting some risks,
- The risk of doctors not noticing a report with cancer, because the report is outnumbered with useless words about breast density and birads numbers and which society or government set the guidelines, and so on.
- The risk of having more people die due to annoyance and confusion about mammograms
Here’s an example, from where I live, in the Province of Alberta, Canada. If a government sets a clear guideline that women should get mammograms ever 1 year, what happens? Women tend to come every 2 years. Some women develop a cancer during those 2 years, and some will die because of it. If a government sets a guideline that women under 50 can have mammograms annually, and rest can have mammograms every 2 years, what happens? Women tend to come every 5 years. During those 5 years, more cancers and more deaths.
By the way, this is a fact, and let me reference it. This is data from the Alberta Breast Cancer Screening Program, presented to the Alberta Society of Radiologists meeting in 2013 or 2014. Major screening programs and governments find this embarrassing, (and financially beneficial), so data like this doesn’t get publicity or published in journals.
Another example. Every few years, there will be some scientific study published somewhere, saying that mammography doesn’t prevent cancer deaths. A flurry of scientific rebuttals and arguing will appear in the medical journals for months afterwards. But normal people see none of that. Instead, normal people see a TV reporter telling women that mammograms don’t benefit, and they may see 2 doctors arguing about it on TV. The result? Women stop coming for mammograms for about 5 years, and during those 5 years, cancers happen and go undiagnosed too long, until they are big and involving lymph nodes, and more women die.
Some of you may know that a patchwork of states in the USA have new laws requiring reporting of breast density. Here’s a map from 2014.
In a yellow-color state like Colorado, here’s the kind of message that goes in a letter to women:
“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. This information about the results of your mammogram is given to you to raise your awareness and to inform your conversations with your doctor. Together, you can decide which screening options are right for you. A report of your results was sent to your physician.”
That letter will confuse women. It also confuses family doctors. I believe states that send confusing letters about mammography, will cause women in the state to have fewer mammograms, and therefore cause more cancer deaths in those states.
My other website Breast-cancer.ca is where most of my breast cancer information has been accumulating.
- Vachon CM, van Gils CH, et al. Mammographic density, breast cancer risk and risk prediction. Breast Cancer Res. 2007 9:217.
- Assi V, Massat NJ, et al. A case-control study to assess the impact of mammographic density on breast cancer risk in women aged 40-49 at intermediate familial risk. Int J Cancer 2014: