By Neely Hines, MD
Associate Chief of Breast Imaging

October is Breast Cancer Awareness Month, an ideal time to learn more about breast cancer screening. As of September 10, 2024, the FDA has mandated that all mammogram reports sent to patients must include their breast density. The density will be described either as “not dense” or “dense.”

It’s important to know what dense breast tissue is. Breasts are made up of fibrous and glandular tissue and fat. Breast density is a measure of how much fibrous and glandular tissue there is in your breast as compared to fat tissue. It has nothing to do with the size or firmness of your breasts. Your hands cannot feel breast density. Density can only be identified on a mammogram.

Fibrous and glandular tissue are more difficult to see through on a mammogram. If your breasts tend to have more fibrous and glandular tissue compared to fat, your breast tissue may be called dense. Having dense breast tissue is common and perfectly normal. About half of the women in the United States who have a mammogram have dense breasts.

Why breast density is important

According to the CDC, women with dense breasts are more likely to get breast cancer than women with less dense breasts. Also, dense breast tissue makes it harder to find breast cancer on a mammogram. This is because both dense breast tissue and breast tumors look white on a mammogram. Breasts with more fatty tissue show up darker, making tumors easier to see.

A mammogram can find breast cancer even if your breasts are dense. Digital 3D mammograms, which are used at Reliant, have been shown to be better at finding breast cancers than regular mammograms. This is because they use many X-rays to make three-dimensional pictures of the breast.

Learn the Types of Breast Density

There are different types of breast density. They range from almost entirely fatty to extremely dense. The radiologist who reads your mammogram decides how dense your breasts are and then puts them into one of four categories:

Category A: Breasts are almost entirely fatty.

Category B: There are scattered areas of fibroglandular density.

Category C: The breasts are heterogeneously dense which may obscure small masses.

Category D: The breasts are extremely dense, which lowers the sensitivity of mammography.

You should talk with your physician about your breast density and whether screenings in addition to mammograms are right for you. Women who have certain risk factors for breast cancer often require additional screening.

Reliant offers mammography screening services in Worcester, Southborough and Leominster. You can learn more about our mammography services and other breast screening services here. To schedule an appointment, please call (508) 853-2716.