Well, better late than never!! This came to my attention today.
Thermologists have known for decades that dense breast tissue reduces greatly the accuracy of a mammogram and that it is essential to have more than 1 test to assess breast health. My mother for example had a tumour not seen by mammography, which resulted in inappropriate last minute treatment and pre-mature death at age 51.
In Spain they already have to report on dense breast tissue so you can decide whether or not you want to have your breasts irradiated or not for the small chance they might find something or not, and now The States are going to do the same. Maybe too many court cases from angry and sick women??
My advice: thermography (test of how your breasts are functioning) together with ultrasound (test of structure) and a physical breast exam. Preferably yearly and starting in your early 30ties. Mammograms are old hat and not safe. MRI would be the ultimate test when something suspicious is found.