Understanding Breast Density.
Breast density refers to the amount of supportive fibrous and glandular tissue in the breast, relative to the quantity of fatty tissue. The more dense supportive tissue present, the more dense the breast is. Density cannot be measured by the look or feel of the breast and is completely normal.
Breast density is categorised into four categories according to the Breast Imaging Reporting & Data System (BI-RADS), from A-D; A being mostly fatty and D being mostly dense tissue.
Breast density is currently determined by radiologists from a mammogram image.
It is estimated that around 40% of women have dense breasts, but this area is still being researched and this figure varies across the world (1).
Density and Mammography.
High breast density can obscure cancer on a mammogram. As X-rays move through tissue, they find it more difficult to penetrate dense structures, making them appear white on a mammogram image. As both tumours and fibroglandular tissue are dense, this can make it hard for cancer to be seen on a mammogram in women with extremely dense breasts.
In the category A breast (fatty), you can see a small, white circular mass in contrast to the fatty tissue, which appears dark and transparent. This circled area represents a potential tumour. As the density increases towards category D, displaying the highest density category, it gets harder to distinguish the tumour from the dense tissue in the image.
Women with very dense breasts can be referred for an alternative scanning method, such as MRI, Ultrasound or contrast-enhanced mammography. These techniques are more sensitive at cancer detection in dense breasts. However, this referral is not a standardised pathway, as there is no way to determine density before a mammogram.
Image Courtesy of Matt Covington, MD and My Density Matters
Density and Breast Cancer Risk.
Breast density is a risk factor for breast cancer. Women with the highest density category are more at risk than women with lower breast density, and risk increases as density increases. (2)
Other risk factors for breast cancer include age, family history of breast or ovarian cancer, and lifestyle and hormonal factors. (3)
Standard breast cancer risk calculators found online do include breast density; however, healthcare professionals can only input this data if the individual has had a mammogram. In the UK, this means waiting until the age of 50 when mammography screening starts.
Even after screening starts, women in the UK are not informed if they have dense breasts.
Women are not informed about their denisty.
Despite breast density being a well-established risk factor for breast cancer and the known masking effects of dense tissue, the only way to measure density routinely is from a mammogram, and women are not informed about their density after the scan.
This makes vital density data hard to obtain for healthcare professionals and leaves women in the dark regarding their breast health and cancer risk.
What is the solution?
A novel method of measuring breast density quickly and safely, making breast density data accessible for all. Women deserve personalised care and to be fully informed about their breast cancer risk, and Micrima’s mission is to provide the data and tools to make this a reality.
References
1. NIH - National Cancer Institute
2. www.NHS.co.uk
3. Cancer Epidemiol Biomarkers Prev (2007) 16 (1): 43–49. Mammographic Breast Density as a General Marker of Breast Cancer Risk
Having dense breast tissue alone is not a cause for concern. If you have any concerns, please speak with your healthcare provider about your breast tissue density and how it affects your risk status.