What is breast density and how is it associated with cancer? Explained Premium
Breasts comprise three types of tissue: fatty tissue, glandular tissue and fibrous connective tissue. Breast density, as per the American Cancer Society, is a measure of how much fibrous and glandular tissue (also known as fibroglandular tissue) there is in your breast, as compared to fatty tissue. This is not related to breast size or firmness. A person with dense breast tissue has more fibrogladular tissue relative to fatty tissue.
There are four categories of breast density: Category A: Breasts are almost entirely all fatty tissue; Category B: Breasts have scattered fibroglandular tissue, but the majority is fatty tissue; Category C: Many areas of the breast have dense fibroglandular tissue (heterogeneously dense) while some areas have fatty tissue; and Category D: Extremely dense breast tissue, almost all of the areas have dense tissue
There are two main reasons: The first is that dense breast tissue makes it harder to detect signs of cancer on a mammogram. This is because dense breast tissue looks white on a mammogram. Masses and cancers in the breast can also look white, making them harder to see, if the breast is dense. Fatty tissue however, looks almost black on a mammogram, making it easier to spot a white tumour/mass, says the American Cancer Society.
However, Bhawna Dev, professor lead consultant, breast imaging and interventions, Sri Ramachandra Medical College, Chennai, says newer technology such as tomosynthesis has decreased the chances of missing cancers as the imagery is more detailed. Digital mammograms, which are also common these days, have better sensitivity compared to conventional mammograms, making them more accurate. There still remain chances though, she says, that small cancers may be missed in the case of extremely dense breasts.
Under the new FDA rule, patient summaries in mammograms will now include the statement: Dense tissue makes it harder to find breast cancer on a mammogram and also raises the risk of developing breast cancer. For women with breast tissue, the disclosure reads: “In some people with dense tissue, other imaging tests in addition to a mammogram may help find cancers. Talk to your healthcare provider about breast density, risks for breast cancer, and your individual situation.”
The second reason breast density is significant is because it is associated with an increased risk of breast cancer. “Multiple studies have shown that increased density is an independent risk factor for breast cancer; however, it must be noted that increased breast density is not associated with increased mortality from breast cancer,” says Dr. Krishnamurthy.
Only a mammogram can tell you if you have dense breasts. It is not something you can self diagnose.
However, women who have any symptoms related to the breast or those who have one or more risk factors should consult a doctor and then get a mammogram done if required, emphasise doctors.
Should all women whose mammogram indicates dense breasts get additional screening? Not necessarily, says Dr. Krishnamurthy. Women who have a high risk of breast cancers will benefit from additional imaging such as tomosynthesis, an MRI of the breast or an ultrasound as deemed clinically necessary by their treating physician.
Published - November 02, 2024 11:10 am IST