October is Breast Cancer Awareness Month. As a family medicine physician, I get a lot of questions about mammograms – a commonly used screening test for breast cancer. Often, questions are related to the mammogram finding of dense breast tissue.

Breasts are generally made up of 3 types of tissue: glandular tissue, fibrous connective tissue and fatty tissue. Dense breasts have relatively more glandular and connective tissue than fatty tissue. Almost 50 % of women 40 years and older have dense breast tissue so it’s a very common finding on mammograms. Dense breast tissue is benign (non cancerous).

Mammograms can be harder to read if a woman has dense breasts because findings like tumors and calcifications look similar to glandular and connective tissue. This may result in more frequent recommendations for further evaluation after a routine mammogram (e.g. additional imaging or biopsy).

For similar reasons, screening mammograms are more likely to miss a breast cancer with dense breast tissue.

While it is a common and normal condition, there is an increased risk of breast cancer for women with dense breasts. Experts are not yet sure why dense breasts increase the risk of breast cancer. Experts also do not agree on if and what additional screening should be done due to this increased risk.

You should still get mammograms to screen for cancer. Speak with your provider about your mammogram report and whether or not you have dense breasts. Review your personal and family history with him/her to determine your overall risk and to see if additional imaging is needed for breast cancer screening.

Your healthcare provider is a great resource.

The information above was taken from the following links. They have much more to offer on the topic.

-The NIH’s National Cancer Institute:

https://www.cancer.org/cancer/types/breast-cancer/screening-tests-and-early-detection/mammograms/breast-density-and-your-mammogram-report.html

-The American Cancer Society:

https://www.cancer.gov/types/breast/breast-changes/dense-breasts#are-dense-breasts-a-risk-factor-for-breast-cancer