WE HAVE LONG KNOWN THAT BREAST DENSITY is associated with the risk of getting breast cancer. Researchers recently discovered a new breast cancer risk factor. Breast density typically declines with age, but a slower rate of decline in one breast often precedes a cancer diagnosis in that breast. Today, we examine a new breast cancer risk factor.
This article will distinguish the various types of breast tissue, breast density, and the new research findings.
“Absence is a house so vast that inside you will pass through its walls and hang pictures on the air.” ― Pablo Neruda.
What are the breast’s tissues?
A woman’s breast has three kinds of tissue, including the following:
- Fibrous tissue holds the breast tissue in place.
- Glandular tissue is the part of the breast that makes milk called the lobes. The tubes that carry milk to the nipple are called ducts. Together, fibrous and glandular tissue are called fibroglandular tissue.
- Fatty tissue fills the space between the fibrous tissue, lobes, and ducts. It gives the breasts their size and shape.
What is breast density?
Breast density refers to the composition of breast tissue, which can be seen on a mammogram. It is determined by the ratio of fatty tissue to glandular and fibrous tissue in the breasts. The breast appears white on a mammogram, and dense breast tissue also appears white, making it more challenging to detect abnormalities or tumors.
Breast density is classified into four categories:
- Fatty. Breasts with a higher proportion of fatty tissue and less glandular and fibrous tissue. Fatty breasts appear mostly dark on a mammogram, and abnormalities are easier to detect.
- Scattered fibroglandular density. Breasts with a mix of fatty and glandular/fibrous tissue. In this category, there is a moderate amount of glandular and fibrous tissue that may slightly obscure the visualization of abnormalities.
- Heterogeneously dense. Breasts with a significant amount of glandular and fibrous tissue make it harder to identify abnormalities on a mammogram. Heterogeneously dense breasts appear mostly white with some areas of darker fatty tissue.
- Extremely dense. Breasts with a large amount of glandular and fibrous tissue make detecting abnormalities on a mammogram difficult. Extremely dense breasts appear almost entirely white, and any abnormalities may be obscured.
Incidence of breast density types
Here are the incidences for each of the four density types, according to Memorial Sloan Kettering Cancer Center (USA):
- About one out of every ten women have very dense breasts.
- Around four out of every ten women have heterogeneous density. That means their breasts are mostly dense, with some areas of fat.
- Another four out of every ten women have scattered density. That means some areas are dense, but most are not.
- About one out of every ten women have breasts that are mostly fat. They have no fibrous and glandular tissue or very little.
Breast density is an important factor in breast cancer screening, as women with higher breast density are known to have a slightly increased risk of developing breast cancer.
Dense breasts are also associated with a lower sensitivity of mammography, as the dense tissue may mask tumors. Additional screening methods such as ultrasound or magnetic resonance imaging (MRI) may be recommended for women with dense breasts to improve the detection of breast cancer.
What causes breast cancer?
Breast cancer is a complex disease that arises from various factors, including genetic, hormonal, and environmental influences. One of the primary causes of breast cancer is genetic mutations.
Certain genes, such as BRCA1 and BRCA2, are responsible for suppressing the growth of tumors. When mutations occur in these genes, they can no longer carry out their tumor-suppressing functions effectively, increasing the risk of breast cancer development. Other genetic variations and inherited gene mutations can also contribute to the risk of developing breast cancer.
Hormonal factors play a significant role in breast cancer development as well. Estrogen and progesterone, female sex hormones, regulate the growth and development of breast tissue. Prolonged exposure to high levels of these hormones can increase the risk of breast cancer.
Factors that can lead to increased hormone exposure include early onset of menstruation, late onset of menopause, late age at first childbirth, and long-term hormone replacement therapy. Furthermore, certain hormonal disorders, such as polycystic ovary syndrome (PCOS), can also influence hormone levels and potentially increase the risk of breast cancer.
It’s important to note that while certain risk factors may increase the likelihood of developing breast cancer, they don’t guarantee its occurrence. Many individuals with breast cancer may not have any identifiable risk factors, emphasizing the need for regular screenings and early detection methods to ensure timely diagnosis and treatment.
Who Is More Likely to Have Dense Breasts?
Breast density can change over time. In general, you are more likely to have dense breasts if you —
- Are taking hormone replacement therapy.
- Are younger.
- Are taking hormone replacement therapy.
- Have a lower body weight.
Why is breast density important?
Breast Cancer Risk
Women with dense breasts have an elevated breast cancer risk. The denser the breasts, the higher the risk. Scientists don’t know for sure why this is the case.
Breast cancer patients with dense breasts are not more likely to die from breast cancer than patients with non-dense (fatty) breasts.
Mammograms
Dense tissue can hide cancers. Fibrous and glandular tissue looks white on a mammogram. So does a possible tumor. Because it’s hard to tell the difference between a tumor and dense breast tissue on a mammogram, a small tumor may be missed.
Breast density — New findings
A recent study in JAMA Oncology offers a fascinating new insight:
While breast density typically declines with age, a slower rate of decline in one breast (than the other) often precedes a cancer diagnosis in that breast.
Washington University (St. Louis, USA) researchers examined breast density changes over a decade. The study enrolled 10,000 cancer-free women.
Over ten years, 289 women received a breast cancer diagnosis. The study analyzed changes in their breast tissue compared to those in 658 similar women who did not develop breast cancer.
Not surprisingly, breast density was higher from the start in the women who went on to develop breast cancer. Density declined in all women over time.
But when researchers measured each breast’s density separately, they discovered a significantly slower decline in density in breasts that developed cancer compared to the other breast in the same patient.
What Should I Do If I Have Dense Breasts?
Talk to your healthcare provider about your risk. Dense breasts are one of several breast cancer risk factors. Age and family history of cancer are among the other factors affecting risk.
Supplemental imaging can detect some cancers that a mammogram misses. Magnetic resonance imaging (MRI) and ultrasound are examples; however, such tests are more likely to have a false positive result (the test is reported as abnormal, but you don’t have cancer). False positive test results often lead to unnecessary tests, such as a biopsy.
Dense breast tissue: What it is, and what to do if you have it
You may have dense breast tissue without knowing it, but it can impact breast cancer screenings. Ethan Cohen, M.D…www.mdanderson.org
Also, chat with your healthcare provider about how often you should be screened for breast cancer and which tests your doctor recommends.
Key points — A New Breast Cancer Risk Factor
Question. Are breast density changes over time associated with breast cancer risk?
Findings. This is the first study analyzing breast density changes, over time, in an individual breast (rather than averaging the two breasts). While breast density typically declines with age, a slower rate of decline in one breast (than the other) often precedes a cancer diagnosis in that breast.
Meaning. While we currently provide women with information about breast density (and associated risks), this study offers the promise of using breast density information in better ways. We may someday offer screening (and other management) recommendations based on an individual woman’s risk.
If you know someone with breast cancer, here is my comprehensive online course:
Breast Cancer – What a Patient Needs to Know.
Breast cancer information can be incredibly valuable for navigating breast cancer management. breastcancerbydrhunter.thinkific.com.
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The information I provided in this blog is for educational purposes only and does not substitute for professional medical advice. Please consult a medical professional or healthcare provider for medical advice, diagnoses, or treatment. I am not liable for risks or issues associated with using or acting upon the information in this blog.
Thank you for reading “A New Breast Cancer Risk Factor.”
