Tag: diagnostic imaging

CNN
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Breast density is known to naturally decrease as a woman ages, and now a study suggests that the more time it takes for breast density to decline, the more likely it is that the woman could develop breast cancer.

Researchers have long known that women with dense breasts have a higher risk of breast cancer. But according to the study, published last week in the journal JAMA Oncology, the rate of breast density changes over time also appears to be associated with the risk of cancer being diagnosed in that breast.

“We know that invasive breast cancer is rarely diagnosed simultaneously in both breasts, thus it is not a surprise that we have observed a much slower decline in the breast that eventually developed breast cancer compared to the natural decline in density with age,” Shu Jiang, an associate professor of surgery at Washington University School of Medicine in St. Louis and first author of the new study, wrote in an email.

Breast density refers to the amount of fibrous and glandular tissue in a person’s breasts compared with the amount of fatty tissue in the breasts – and breast density can be seen on a mammogram.

“Because women have their mammograms taken annually or biennially, the change of breast density over time is naturally available,” Jiang said in the email. “We should make full use of this dynamic information to better inform risk stratification and guide more individualized screening and prevention approaches.”

The researchers, from Washington University School of Medicine in St. Louis and Brigham and Women’s Hospital in Boston, analyzed health data over the course of 10 years among 947 women in the St. Louis region who completed routine mammograms. A mammogram is an X-ray picture of the breast that doctors use to look for early signs of breast cancer.

The women in the study were recruited from November 2008 to April 2012, and they had gotten mammograms through October 2020. The average age of the participants was around 57.

Among the women, there were 289 cases of breast cancer diagnosed, and the researchers found that breast density was higher at the start of the study for the women who later developed breast cancer compared with those who remained cancer-free.

The researchers also found that there was a significant decrease in breast density among all the women over the course of 10 years, regardless of whether they later developed breast cancer, but the rate of density decreasing over time was significantly slower among breasts in which cancer was later diagnosed.

“This study found that evaluating longitudinal changes in breast density from digital mammograms may offer an additional tool for assessing risk of breast cancer and subsequent risk reduction strategies,” the researchers wrote.

Not only is breast density a known risk factor for breast cancer, dense breast tissue can make mammograms more difficult to read.

“There are two issues here. First, breast density can make it more difficult to fully ‘see through’ the breast on a mammogram, like looking through a frosted glass. Thus, it can be harder to detect a breast cancer,” Dr. Hal Burstein, clinical investigator in the Breast Oncology Center at Dana-Farber Cancer Institute, who was not involved in the new study, said in an email. “Secondly, breast density is often thought to reflect the estrogen exposure or estrogen levels in women, and the greater the estrogen exposure, the greater the risk of developing breast cancer.”

In March, the US Food and Drug Administration published updates to its mammography regulations, requiring mammography facilities to notify patients about the density of their breasts.

“Breast density can have a masking effect on mammography, where it can be more difficult to find a breast cancer within an area of dense breast tissue,” Jiang wrote in her email.

“Even when you take away the issue of finding it, breast density is an independent risk factor for developing breast cancer. Although there is lots of data that tell us dense breast tissue is a risk factor, the reason for this is not clear,” she said. “It may be that development of dense tissue and cancer are related to the same biological processes or hormonal influences.”

The findings of the new study demonstrate that breast density serves as a risk factor for breast cancer – but women should be aware of their other risk factors too, said Dr. Maxine Jochelson, chief of the breast imaging service at Memorial Sloan Kettering Cancer Center in New York, who was not involved in the study.

“It makes sense to some extent that the longer your breast stays dense, theoretically, the more likely it is to develop cancer. And so basically, it expands on the data that dense breasts are a risk,” Jochelson said, adding that women with dense breasts should ask for supplemental imaging when they get mammograms.

But other factors that can raise the risk of breast cancer include having a family history of cancer, drinking too much alcohol, having a high-risk lesion biopsied from the breast or having a certain genetic mutation.

For instance, women should know that “density may not affect their risk so much if they have the breast cancer BRCA 1 or 2 mutation because their risk is so high that it may not make it much higher,” Jochelson said.

Some ways to reduce the risk of breast cancer include keeping a healthy weight, being physically active, drinking alcohol in moderation or not at all and, for some people, taking medications such as tamoxifen and breastfeeding your children, if possible.

“Breast density is a modest risk factor. The ‘average’ woman in the US has a 1 in 8 lifetime chance of developing breast cancer. Women with dense breasts have a slightly greater risk, about 1 in 6, or 1 in 7. So the lifetime risk goes up from 12% to 15%. That still means that most women with dense breasts will not develop breast cancer,” Burstein said in his email.

“Sometimes radiologists will recommend additional breast imaging to women with dense breast tissue on mammograms,” he added.

The US Preventive Services Task Force – a group of independent medical experts whose recommendations help guide doctors’ decisions – recommends biennial screening for women starting at age 50. The task force says that a decision to start screening earlier “should be an individual one.” Many medical groups, including the American Cancer Society and Mayo Clinic, emphasize that women have the option to start screening with a mammogram every year starting at age 40.

“It’s also very clear that breast density tends to be highest in younger women, premenopausal women, and for almost all women, it tends to go down with age. However, the risk of breast cancer goes up with age. So these two things are a little bit at odds with each other,” said Dr. Freya Schnabel, director of breast surgery at NYU Langone’s Perlmutter Cancer Center and professor of surgery at NYU Grossman School of Medicine in New York, who was not involved in the new study.

“So if you’re a 40-year-old woman and your breasts are dense, you could think about that as just being really kind of age-appropriate,” she said. “The take-home message that’s very, very practical and pragmatic right now is that if you have dense breasts, whatever your age is, even if you’re postmenopausal – maybe even specifically, if you are postmenopausal – and your breasts are not getting less dense the way the average woman’s does, that it really is a reason to seek out adjunctive imaging in addition to just mammography, to use additional diagnostic tools, like ultrasound or maybe even MRI, if there are other risk factors.”

CNN
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Dense breast tissue has been associated with up to a four times higher risk of breast cancer. However, a new study suggests few women view breast density as a significant risk factor.

The study, published in JAMA Network Open, surveyed 1,858 women ages 40 to 76 years from 2019 to 2020 who reported having recently undergone mammography, had no history of breast cancer and had heard of breast density.

Women were asked to compare the risk of breast density to five other breast cancer risk factors: having a first-degree relative with breast cancer, being overweight or obese, drinking more than one alcoholic beverage per day, never having children and having a prior breast biopsy.

“When compared to other known and perhaps more well-known breast cancer risks, women did not perceive breast density as significant of a risk,” said Laura Beidler, an author of the study and researcher at the Dartmouth Institute for Health Policy and Clinical Practice.

For example, the authors report that dense breast tissue is associated with a 1.2 to four times higher risk of breast cancer compared with a two times higher risk associated with having a first-degree relative with breast cancer – but 93% of women said breast density was a lesser risk.

Dense breasts tissue refers to breasts that are composed of more glandular and fibrous tissue than fatty tissue. It is a normal and common finding present in about half of women undergoing mammograms.

The researchers also interviewed 61 participants who reported being notified of their breast density and asked what they thought contributes to breast cancer and how they could reduce their risk. While most women correctly noted that breast density could mask tumors on mammograms, few women felt that breast density could be a risk factor for breast cancer.

Roughly one-third of women thought there was nothing they could do to reduce their breast cancer risk, although there are several ways to reduce risk, including maintaining a healthy, active lifestyle and minimizing alcohol consumption.

Breast density changes over a woman’s lifetime, and is generally higher in women who are younger, have a lower body weight, are pregnant or breastfeeding, or are taking hormone replacement therapy.

The level of breast cancer risk increases with the degree of breast density; however, experts aren’t certain why this is true.

“One hypothesis has been that women who have more dense breast tissue also have higher, greater levels of estrogen, circulating estrogen, which contributes to both the breast density and to the risk of developing breast cancer,” said Dr. Harold Burstein, a breast oncologist at the Dana-Farber Cancer Institute who was not involved in the study. “Another hypothesis is that there’s something about the tissue itself, making it more dense, that somehow predisposes to the development of breast cancer. We don’t really know which one explains the observation.”

Thirty-eight states currently mandate that women receive written notification about their breast density and its potential breast cancer risk following mammography; however, studies have shown that many women find this information confusing.

“Even though women are notified usually in writing when they get a report after a mammogram that says, ‘You have increased breast density,’ it’s kind of just tucked in there at the bottom of the report. I’m not sure that anyone is explaining to them, certainly in person or verbally, what that means,” said Dr. Ruth Oratz, a breast oncologist at NYU Langone’s Perlmutter Cancer Center who was not involved in the study.

“I think what we’ve learned from this study is that we have to do a better job of educating not only the general public of women, but the general public of health care providers who are doing the primary care, who are ordering those screening mammograms,” she added.

Current screening guidelines recommend women of average risk of breast cancer undergo breast cancer screening every one to two years between ages 50 to 74 with the option of beginning at age 40.

Because women with dense breast tissue are considered to have higher than average cancer risks, the authors of the study suggest women with high breast density may benefit from supplemental screening like breast MRI or breast ultrasound, which may detect cancers that are missed on mammograms. Currently, coverage of supplemental screening after the initial mammogram varies, depending on the state and insurance policy.

The authors warn that “supplemental screening not only can lead to increased rates of cancer detection but also may result in more false-positive results and recall appointments.” They say clinicians should use risk assessment tools when discussing tradeoffs associated with supplemental screening.

“Usually, it’s a discussion between the patient, the clinical team, and the radiologist. And it’ll be affected by prior history, by whether there’s anything else of concern on the mammogram, by the patient’s family history. So those are the kinds of things we discuss frequently with patients who are in such situations,” Burstein said.

Breast cancer screening recommendations differ between medical organizations, and experts say women at higher risk due to breast density should discuss with their doctor what screening method and frequency are most appropriate.

“I think it’s really, really important that everyone understands – and this is the doctors, the nurses, the women themselves – that screening is not a one size fits all recommendation. We cannot just make one general recommendation to the entire population because individual women have different levels of risks of developing breast cancer,” Oratz said.

For the nearly one-third of women with dense breast tissue that reported there was nothing they could do to prevent breast cancer, experts say there are some steps you can take to reduce your risk.

“Maintaining an active, healthy lifestyle and minimizing alcohol consumption address several modifiable factors. Breastfeeding can decrease the risk. On the other hand, use of hormone replacement therapy increases breast cancer risk,” said Dr. Puneet Singh, a breast surgical oncologist at the MD Anderson Cancer Center who was not involved in the study.

The researchers add that there are approved medications, such as tamoxifen, that can be given for those at significantly increased risk that may reduce the chances of breast cancer by about half.

Finally, breast cancer doctors say that in addition to appropriate screening, knowing your risk factors and advocating for yourself can be powerful tools in preventing and detecting breast cancer.

“At any age, if any woman feels uncomfortable about something that’s going on in her breast, if she has discomfort, notices a change in the breast, bring that to the attention of your doctor and make sure it gets evaluated and don’t let somebody just brush you off,” Oratz said.