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Why Does Dense Breast Tissue Increase Cancer Risk

Is There An Increased Risk Of Breast Cancer If I Have Dense Breast Tissue

Does Dense Breast Tissue Raise Cancer Risk? Dr. Neil B. Friedman, Mercy Medical Center Baltimore

There may be a slightly increased risk for breast cancer if you have dense breast tissue. Healthcare professionals have not yet been able to prove why that is. Having dense tissue can also make it harder for radiologists to see breast cancer because it can be hidden by the similar appearing dense tissue.

Dense Breasts And Breast Cancer Risk

Breast cancer is the second-most common cancer affecting American women. In fact, 1 in 8 women receives a breast cancer diagnosis in her lifetime. To protect your health, preventive care is important.;

Women over 45 and those with a family history of breast cancer should get mammogram screenings regularly. Mammograms are one of the best ways to detect early signs of breast cancer, when its most treatable.

But if youve had a mammogram and were told that you have dense breasts, you might be wondering what that means for your health. Our OB/GYN team at The Womens Center can help you understand your risk of breast cancer.;;

Dense breast tissue often makes mammogram screenings less effective, because the tissue is hard to see through. But does having dense breasts mean youre more likely to develop breast cancer?

How Does Breast Density Compare To Other Risk Factors For Developing Invasive Breast Cancer

The charts below detail relative risk and prevalence .

Relative Risk:;The top chart shows approximate relative risk of developing invasive breast cancer by age 80 for a woman with a given risk factor compared to a woman without that risk factor: 1) disease-causing;BRCA1;or -2 mutation; 2) prior ductal carcinoma in situ; 3) prior atypical ductal hyperplasia; 4) first-degree relative diagnosed with breast cancer by age 50; 5) combined estrogen and progesterone therapy after menopause; 6) heterogeneously dense breast tissue ; or 7) extremely dense breast tissue .

*The 15-year risk of developing invasive breast cancer among women with untreated DCIS is about 10 times greater than the risk in the general population . The risk 3 years or more after DCIS diagnosis in women who receive standard treatment is nearly 3 times greater than the risk in the general population .

Prevalence:;The lower chart shows estimated prevalence of each risk factor in American women aged 40-74, except for hormone replacement therapy which applies only to postmenopausal women. Dense breast tissue is quite common, seen in 43% of all women aged 40-74.

References Cited

1. Cummings SR, Tice JA, Bauer S, et al. Prevention of breast cancer in postmenopausal women: Approaches to estimating and reducing risk. J Natl Cancer Inst2009; 101:384-398

2. Couch FJ, DeShano ML, Blackwood MA, et al. BRCA1 mutations in women attending clinics that evaluate the risk of breast cancer. N Engl J Med1997; 336:1409-1415

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D Mammography Breast Ultrasound And Breast Mri

Some data suggest 3D mammography may find more breast cancers in women with dense breasts compared to 2D mammography .

Breast ultrasound and breast MRI are being studied to learn whether they improve detection in women with dense breasts compared to mammography alone .

More research is needed to understand the benefits and harms of using these imaging tests for women with dense breasts .

*Please note, the information provided within Komen Perspectives articles is only current as of the date of posting. Therefore, some information may be out of date.

Should Women With Dense Breasts Have Additional Screening For Breast Cancer

Mammogram study: Dense breasts won

In some states, mammography providers are required to inform women who have a mammogram about breast density in general or about whether they have dense breasts. Many states now require that women with dense breasts be covered by insurance for supplemental imaging tests. A United States map showing information about specific state legislation is available from

Nevertheless, the value of supplemental, or additional, screening tests such as ultrasound or MRI for women with dense breasts is not yet clear, according to the Final Recommendation Statement on Breast Cancer Screening by the United States Preventive Services Task Force. Ongoing clinical trials are evaluating the role of supplemental imaging tests in women with dense breasts. NCIâs Cancer Information Service can tell you about clinical trials and provide tailored clinical trial searches to help you learn more about clinical trials related to breast density and breast cancer screening.

Recent research has suggested that for women with dense breasts, a screening strategy that also takes into account a womanâs risk factors and protective factors may be the best predictor of whether a woman will develop breast cancer after a normal mammogram and before her next scheduled mammogram.

As you talk with your doctor about your personal risk for breast cancer, keep in mind that:

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Why Does Breast Density Matter

Dense breasts make it harder for radiologists to detect breast cancers when they read a mammogram. Cancers typically show up as small white spots or masses on a mammogram. Dense breast tissue also appears white on a mammogram. Small areas of cancer can hide behind the dense tissue, and its challenging to tell the difference between normal, healthy tissue and abnormal growths. The organization compares it to trying to see a snowman in a blizzard. Fatty breast tissue appears dark on a mammogram, so areas of concern that show up white are much easier to see.

Mammograms can miss about half of cancers in women with dense breasts.3, 4 In addition, women with dense breasts are more likely to be diagnosed with breast cancer within the year after receiving a normal mammogram result, usually based on symptoms such as a lump or other breast changes.

Apart from hiding cancers on mammograms, dense breast tissue itself is associated with a higher risk of breast cancer. Doctors arent sure exactly why. Cancers develop in glandular tissue: the more glandular tissue there is, the greater the risk. Fibrous tissue may also produce growth factors that cause glandular tissue cells to divide and reproduce more than cells in fatty tissue do. Every time a cell divides, there is an opportunity for a mistake in the DNA to occur in the new cells and multiple mistakes can eventually result in cancer.

Here Are Answers To Common Questions About Dense Breast Tissue:

What is dense breast tissue?

Dense breast tissue refers to the appearance of breast tissue on a mammogram. It’s a normal and common finding.

Breast tissue is composed of milk glands, milk ducts and supportive tissue. These elements make up the dense tissue in the breast. Breasts also include fatty tissue, which is nondense tissue. When viewed on a mammogram, women with dense breasts have more dense tissue than fatty tissue.

On a mammogram, nondense breast tissue appears dark and transparent. Dense breast tissue appears as a solid white area on a mammogram, which makes it difficult to see through.

How do doctors determine if you have dense breast tissue?

The radiologist who analyzes your mammogram determines the ratio of nondense tissue to dense tissue and assigns a level of breast density. Levels of density are described using a results reporting system called Breast Imaging Reporting and Data System, as provided by the American College of Radiology.

The levels of density are often recorded in your mammogram report using letters:

In general, women with breasts that are classified as heterogeneously dense or extremely dense levels C and D are considered to have dense breasts. About half of women undergoing mammograms have dense breasts.

What causes dense breast tissue?

It’s not clear why some women have a lot of dense breast tissue and others do not. You may be more likely to have dense breasts if you:

Why does breast density matter?

Are other tests more effective?

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Family History Presents Small Risk

The most significant finding in this study is the impact of breast density on development of breast cancer in the population, said senior author Karla Kerlikowske, MD, professor of medicine and of epidemiology and biostatistics in the UCSF Helen Diller Family Comprehensive Cancer Center. We found that if breast density could be reduced by a single BI-RADS category, 13.4 percent of breast cancers in both pre-menopausal and post-menopausal women could be averted. Finding interventions that can reduce breast density, such as breastfeeding and/or increased number of children and birth of children before age 30, could contribute to preventing more cases than reducing any other risk factor in the study.

According to the Centers for Disease Control and Prevention, 230,815 women were diagnosed with breast cancer and 40,860 died from it in 2013. In the same year 2,109 men were diagnosed with breast cancer and 464 died from it.

The study was supported by the National Cancer Institute-funded Program Project grant P01 CA154292.

Study co-authors are Marzieh Golmakani of the University of California, Davis; Diana Miglioretti PhD, of the University of California, Davis, and the Group Health Research Institute in Seattle; and Brian Sprague, PhD, of the University of Vermont in Burlington.;

Does Breast Density Change Over Time

Dense breast tissue raises cancer risk

Breast density can change throughout a womans life. For some women, the breasts may become more fatty as they get older. Others may have increased density for example, density may increase in women who use hormone replacement therapy in the post-menopausal years. Some women may have no change in their density.

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Many Women With Dense Breasts May Not Need Additional Screening

Although dense breast tissue, which appears white on mammograms, can mask the presence of tumors, a new study suggests that having dense breasts alone may not be a reason for additional screening.

Women with dense breasts are at increased risk of breast cancer, and high breast density is a cause of false-negative results on a standard screening mammography. However, results from a new study suggest that breast density alone should not dictate whether women should receive additional screening for breast cancer after a normal result on a screening mammogram.

Rather, the NCI-supported study found, for women with dense breasts, a screening strategy that also takes into account other risk factors is the best predictor of developing a breast cancer after a negative mammogram and before their next mammogram, often referred to as an interval cancer.

We found that for the vast majority of women undergoing mammographyincluding those with dense breasts but low 5-year breast cancer riskthe chance of developing breast cancer within 12 months of a normal mammogram was low, the studys lead investigator, Karla Kerlikowske, M.D., of the University of California, San Francisco, said.

Similar federal legislation is currently being considered by Congress. Although these additional imaging procedures can detect cancers missed by mammography, their use has also been found to increase false-positive results and to lead to additional procedures, including unnecessary biopsies.

Higher Bmi Linked To Lower Density

Typically women with a high BMI have lower breast density, though age is a strong determinant of breast density as well, said first author Natalie Engmann, a PhD candidate in the UCSF Department of Epidemiology and Biostatistics. Dense breasts are more common in younger women and most women experience a sharp decline during menopause that continues in the post-menopausal period. However, post-menopausal estrogen and progestin therapy can reverse the decline of breast density with age.

The researchers compared the population attributable risk of breast cancer risk factors, which assesses the impact of each risk factor on the development of disease in an entire population. They calculated the effect of each risk factor, using 18,437 women with breast cancer, compared to 184,309 women of the same age who did not have the disease.

They found that breast density was the most prevalent risk factor and that 39.3 percent of breast cancers in pre-menopausal women and 26.2 percent in post-menopausal women had the potential to have been prevented if all women with higher breast density, BI-RADS categories C and D, had been shifted to lower-density BI-RADS category B.

The researchers found that 22.8 percent of breast cancers in this group could have been averted if obese and overweight women attained a body mass index of less than 25, the equivalent of 155 lbs for a woman of 5 feet 6 inches.

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Specifically The Study Found That Of The Over 500000 Women Screened The Breast Cancer Risk Was 3 Times Higher For Post

What You Can Do

;If you discover that you have extremely dense breasts, know that studies indicate that your chances of Breast Cancer may be higher than normal. Here is what you can do to be Proactive with Prevention:

  • Get checked using thermography and blood tests regularly. I recommend thermography as an;early An example of a thermography image.

    prevention tool of choice for any woman on a Healthy Breast path. The NCI report regarding mammogram and Dense Breasts is largely concerned with mammograms tendency to issue false negatives for women with dense breast tissue. While no prevention tool is 100% correct all of the time, thermographys use of infrared heat to detect inflammation and physiological changes;means that this method can spot possible cancerous activity six to eight years prior to the appearance of any palpable mass. The tumor size may be the size of a pinhead, but it is laying the foundation for future;cancer growth.;

  • Do not use synthetic Hormone Replacement Therapy. I do not recommend synthetic HRT for any woman since studies have clearly made the connection between it and cancer as well as heart disease; I especially do not recommend it for women with extremely dense breast tissue. If you are considering HRT as an option, try Bio-Identical Hormone Replacement Therapy instead.;Work with a physician who tests and monitors your hormones through saliva testing.;

Breast Density May Be Top Indicator Of Cancer Risk

New U Women

Study suggests it outweighs obesity and family history, but oncologists say more research is needed

HealthDay Reporter

THURSDAY, Feb. 2, 2017 — Women whose breasts are predominantly made up of more dense, glandular tissue face higher odds for breast cancer, a new study finds.

The researchers added that, based on their study of 200,000 women, breast density may be the most important gauge of breast cancer risk, eclipsing family history of the disease and other risk factors.

“The most significant finding in this study is the impact of breast density on development of breast cancer in the population,” said study senior author Dr. Karla Kerlikowske. She is a researcher in the department of epidemiology and biostatistics at the University of California, San Francisco .

Still, not everyone is convinced that breast tissue density is the preeminent risk factor for breast cancer.

Dr. Kristin Byrne is chief of breast imaging at Lenox Hill Hospital in New York City. She believes that the numbers in the study attributed to risk based on tissue density seem “incredibly high, especially when other risk factors were not taken into consideration.”

Byrne said, “Before these patients are placed on drugs such as tamoxifen, which have significant side effects and are intolerable for many people, more studies are necessary.”

Overall, breast density was the most prevalent risk factor for breast cancer, the UCSF team reported.

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Characteristics Of Dense Breasts

Breasts are composed of fibrous, glandular, and fatty tissue. A woman’s breasts are considered dense if they have less fat and more glandular and fibrous tissue than average.

There are four categories used to describe breast density:

  • Breasts that are the least dense have almost all fatty tissue
  • Breasts that have scattered areas of fibroglandular density
  • Breasts with;heterogeneous;density
  • Breasts that have almost all glandular and fibrous tissue with little to no fatty tissue.
  • Dense breasts are more common among women who are young and postmenopausal women who take hormone therapy for symptoms of menopause.

    Do Dense Breasts Affect The Risk Of Developing Breast Cancer

    Yes. Dense breast tissue is a risk factor for the development of breast cancer: the denser the breast, the higher the risk . A meta-analysis across many studies concluded that magnitude of risk increases with each increase in density category, and women with extremely dense breasts have a 4-fold greater risk of developing breast cancer than do women with fatty breasts , with upper limit of nearly 6-fold greater risk .

    Breast Cancer Risk by Breast Density Category.

    Most women do not have fatty breasts, however. More women have breasts with scattered fibroglandular density . In some populations, denser breasts are more common. For example, Asian women are often reported to have denser breasts than do other races; however, after accounting for age at mammography and BMI, the differences are modest . Women with heterogeneously dense breasts have about a 1.5-fold greater risk of developing breast cancer than those with scattered fibroglandular density , while women with extremely dense breasts have about a 2-fold greater risk.

    Risk for developing breast cancer is influenced by a combination of many different factors including age, family history of cancer , and prior atypical breast biopsies. Most women who develop breast cancer have no additional risk factors other than being female and aging.

    For live links to breast cancer risk assessment tools click;HERE.

    References Cited

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    Impact On Breast Cancer Risk

    Dense breasts are associated with an increased risk of breast cancer.;And the denser a woman’s breasts are, the higher the risk of breast cancer. The reason for this association is not completely clear.

    To give a sense of perspective about the increased risk of breast cancer with dense breasts:

    • Oral contraceptives increase the risk of breast cancer in women 40 to 49 years old by 1.3 times
    • Heterogeneously dense breasts increase the risk by 1.6
    • Extremely dense breasts increase the risk by 2.04
    • A first-degree relative with breast cancer diagnosed before age 40 increases the risk by 3.0

    The Breast Cancer Surveillance Consortium Risk Calculator is a tool used to asses five- and 10-year breast cancer risk based on age, race/ethnicity, family history of breast cancer, history of a benign breast biopsy, and breast density. While part of this calculation, dense breasts are not the strongest risk factor.

    A previous personal history of breast cancer, a family history of breast cancer, and having a genetic mutation associated with breast cancer are all bigger risk factors for breast cancer than dense breasts are.


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