If you’ve recently been told you have dense breasts, you might be feeling a bit confused or worried - yet dense breast tissue is NOT abnormal. In fact, almost half of women have dense breast tissue. Understanding what this means can help you make informed decisions about your health.

What Are Dense Breasts?

Breast density refers to the amount of fibrosis and glandular tissue compared to fatty tissue in the breasts, as seen on a mammogram. Women with dense breasts have more fibrous and glandular tissue, which can make it harder to detect abnormalities like tumors making the accuracy of mammograms lower. Your density is now reported on your mammogram reports, ranging from category A-D. Categories “A” and “B” are considered normal density. Categories “C” and “D” are considered dense.

What Are the Common Causes of Dense Breasts?

Age: Younger women often have denser breasts. As you age, your breast tissue becomes less dense.
Genetics: Your family history can play a role. If your mother or sister has dense breasts, you might too.
Body Mass Index (BMI): Women with lower body fat typically have denser breasts compared to those with higher body fat.
Hormone Levels: Higher levels of estrogen and progesterone can increase breast density. This is why changes can occur during your menstrual cycle, pregnancy, or when taking menopause hormone therapy.

Why Breast Density Matters

Dense breast tissue slightly increases your risk of breast cancer, similar to that of having a relative with a history of breast cancer. Those with category “C” breast tissue density have a risk of breast cancer the same compared to having a second-degree relative (eg, aunt) with breast cancer. Individuals with breast density category “D” (extremely dense), have a risk the same as having a first-degree relative with breast cancer.

How to Determine If Additional Breast Cancer Screening Is Recommended For You

You may be wondering if you should pursue additional screening tests to detect breast cancer, like a breast ultrasound or MRI. This may make sense for some women but the first step is to determine your personal risk of breast cancer. Online calculators like the Tyrer-Cuzick tool are available for you to determine your personal risk.

Now, let’s break down your risk and the current recommendations for additional breast screening. If your lifetime risk for breast cancer is:

Less than 15%: No additional screening beyond mammography is generally recommended.
15-20%: Supplemental screening for your intermediate risk is controversial. The American Cancer Society recommends you discuss the pros/cons of breast ultrasound or abbreviated MRI with your doctor. Since there are no long-term studies that provide data on breast cancer mortality for ultrasound or MRI supplemental screening, additional screening may not be covered by your health insurance plan. We recommend if you decide to proceed with supplemental testing, first, check with your health insurance to avoid a surprise medical bill.
Greater than 20%: Supplemental breast screening is recommended with an MRI yearly (alternate every 6 months with mammogram and then 6 months later with MRI).

The choice belongs to you!

The choice to proceed with supplemental breast screening is a personal one. Once you identify the benefits vs harms and your personal values and goals for additional screening, you can make an informed decision that is right for you. While you can’t change your genetics, you can take steps to decrease your risk of breast cancer. If you would like to learn more, check out our article, Easy Steps to Decrease Your Risk of Breast Cancer.