In my hospice work, I recently met a beautiful young woman who is tragically dying of metastatic breast cancer. Her family asked me and others to share her story in the hope that their experience can help other women. When her cancer was discovered, it had already spread and curative treatment was not possible. She had taken very good care of herself and had always done her annual mammogram. But she was told that her breast cancer had not been detected on her screening mammogram because her breasts are dense.
What are Dense Breasts?
Breast tissue is composed of fatty (nondense) tissue and connective (dense) tissue. About 40% of women who have mammograms have dense breast tissue. On mammograms, fat in the breasts produces a dark background that makes breast cancer, which appears white on mammograms, easier to detect. In contrast, the connective or dense tissue in breasts appears white on mammograms. This makes it harder for radiologists to detect breast cancer. For an illustration of this concept, see images from a website for the non-profit organization Are You Dense?, which seeks to make women aware of how screening mammograms can miss cancer in women with a higher proportion of dense breast tissue.
What Should You Do if Your Breasts Are Dense?
This is a point of debate among experts in breast cancer screening. Performing breast ultrasounds or MRIs in all women with dense breast tissue will detect cancer in some women who have negative screening mammograms. But doing these additional tests will also pick up many false positives, exposing women to unnecessary anxiety and biopsies. Therein, lies the the point of disagreement. Many states, including Texas, have passed laws requiring that radiologists notify women who have dense breasts as observed on screening mammograms. My own take is that we doctors should discuss this issue with women found to have dense breasts on mammograms. We can then work together to make a decision that makes sense to them.