The Dirty Little Secret about Mammograms

Breast density is like mammogram’s dirty little secret. Half of women over 40 have no idea that their “normal” mammogram might not be normal at all. We are looking for a snowball in a snowstorm! You see, cancer is white, and dense tissue is white. So, dense breast tissue can overlap with cancers, masking them from view; in fact, we miss up to 50 percent of cancers in dense breasts. (Kolb, et al.) Secondly, dense tissue is the part of the breast that gets cancer, not fat, so there is a higher risk of getting cancer for women with dense breasts. Density level 4 women have five times the cancer risk as a density level 1. (NEJM)