Three Things to Know About The California Breast Density Law

Posted on December 18, 2015

cali-lawsWhat does it mean when you are told you breasts are dense?

Breasts are made up of a mixture of fat and breast tissue.  The denser the breast, the more breast tissue you have.  Mammograms work by “looking through” the fat to see the breast tissue.  If you have dense breast tissue, particularly in a large breast, it means there are parts of the breast which are not visible.  This is why when they do a mammogram they smash your breast as flat as they can.  They want to see as much of the breast tissue as they can.

Your breast composition changes as you age and with pregnancies.  Usually in older women, the breast becomes fattier.

Having dense breast tissue may increase your risk slightly of getting breast cancer. (This is likely the same reason breast reductions reduce your risk of breast cancer–the more breast tissue you have, the higher the risk a cell can go wayward and change into cancer.)  Mammograms may be less accurate in women with dense breasts, as masses which are benign (okay) and malignant (not okay) both appear white.

What is the rate of breast density?

Radiologists classify breast density using a 4 level density scale:

What should you do if your breasts are dense?

If you have extremely dense breasts, you may want additional screening exams, as mammograms may not be able to see through the entire breast.  The most common other tests are MRI and ultrasound.  Of note, these tests may find things which are not cancer, but when found may require added testing and unnecessary biopsies.  Also the cost of the ultrasound and MRI may not be covered by insurance.  In California since 2013, they have a Breast Density Law.

Points of this law: