Dr. Waina Cheng, M.D. is a medical oncologist for Atlantic Health System's Newton Medical Center.
Q. I recently had my mammogram done. The results mention something about dense breasts. What does that mean and what do I do next?
A. The breast is made up of different types of tissue including skin, glands that make the milk, ducts that transport the milk to the nipple, connective tissue and fat. Increased breast density means that you have more connective tissue, glands and ducts than fat as seen on a mammogram. This is in comparison to women with more fat seen on mammogram or fatty breasts. This is not something you can feel. If you have firm breasts, it does not mean you have dense breasts. Breast density is a finding that can only be seen on a mammogram. About 40 to 50 percent of women eligible for a screening mammogram will have dense breasts. These women are typically younger, less than 50 years old, and have not gone through menopause. Yet there have been instances where mammograms of older women in menopause indicate dense breasts as well.
We know that having dense breasts is a risk factor for developing breast cancer. However, there are other, more important, factors for determining risk including: family history, age, race and reproductive history.
The difficulty with having dense breasts is that it decreases the sensitivity of digital mammograms to detect cancer. For example, mammograms can find 85 percent of cancers in fatty breasts but only 68 percent of cancers in very dense breasts. This is why there are stories of women who are diagnosed with breast cancer months after having a normal mammogram. Most likely, the cancer is there but because of the dense breasts, it is missed.
This is why we are studying other breast imaging methods such as digital breast tomosynthesis, MRI and ultrasound to find the cancers that a mammogram can miss. Digital breast tomosynthesis is a 3-D mammogram. When combined with a digital mammogram, it detects cancers that may have been missed. It also reduces the number of women called back for abnormal mammogram results that are, in fact, normal. This decreases unnecessary biopsies and also anxiety. MRI of the breast is an approved screening tool for patients who have a hereditary breast cancer syndrome. One of the problems, however, is that although an MRI may find more cancer, it is also more likely to find more benign lesions leading to unnecessary biopsies. The same is true for ultrasounds.
If you have dense breasts but no other additional risk factor, the current recommendation is to go for a screening mammogram every one to two years. If you are unclear about your risk factor, please have a discussion with your primary care doctor about undergoing a breast cancer risk assessment. More importantly, KNOW YOUR BREASTS with monthly self-examination. While self-examinations are not a conclusive screening for breast cancer, they are a starting point, and if you feel anything abnormal, you can then follow up with your doctor.
Source : https://www.njherald.com/20181004/ask-the-expert-what-does-it-mean-to-have-dense-breasts521