Every screening mammogram report should include an assessment for breast density. It may include a callback letter requesting you return for further evaluation.
Mammographically, the breasts are made of two types of tissue: fat and fibroglandular tissue (glands and ducts for milk production and the supporting structures and ligaments). By convention from old film screen developed in dark rooms, the fat looks blackish and the fibroglandular tissue looks whitish. Mammography is heavily regulated and the American College of Radiology designates four categories of breast density with an approximated distribution among the general population being:
- Extremely Dense (10%)
- Heterogeneously Dense (40%)
- Scattered Areas of Fibroglandular Density (40%)
- Almost Entirely Fatty Tissue (10%)
The fat generally does nothing, but the fibroglandular tissue is where cancers form. Therefore, the more fibroglandular tissue the greater the chance of developing a cancer. Relative to the general population, there is an approximate 1.2X increased chance of developing breast cancer for women with heterogeneously dense breasts and 2X for women with extremely dense breasts. Of course, this is all massively oversimplified. The younger you are the denser your breasts will appear commensurate with peak child bearing years. Being overweight or underweight will influence the composition of your breasts. There are also genetics and family history to consider when determining a person’s individual risk for potentially developing a breast cancer.
Your breast density should be included in every mammogram report issued. Every report should also include a Breast Imaging – Reporting and Data System (BI-RADS) score. So stay tuned and I will break down the BI-RADS for you later this week.
A personal thought: Women are spectacularly amazing. I could not survive without my wife. I may be a respected physician at work, but at home she is the executive director. In fact, I work closely with our radiology practice, Washoe County Medical Society, and Nevada State Medical Association executive directors, all women, and all outstanding, professional, and well-respected among their peers. I have partnered with hard-working, driven, kind ladies on many group projects and counted myself very fortunate. I just returned from a week at Boy Scout camp with my two oldest boys where the three highest ranking staff members were all hired women. Women, and especially my wife, are very beautiful creatures. Yes, I love my wife more and more, most days…