Dense breast tissue has been linked to an up to four times higher risk of breast cancer. However, a new study suggests that few women consider breast density a significant risk factor.
The study, published in JAMA Network Open, surveyed 1,858 women ages 40 to 76 from 2019 to 2020 who reported having recently had a mammogram, had no history of breast cancer and had heard of breast density.
Women were asked to compare breast density risk 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 had children, and having previously breastfed. biopsy.
“Compared to other known and perhaps more well-known breast cancer risks, women did not see breast density as a significant risk,” said Laura Beidler, an author of the study and a 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 to a two times higher risk associated with having a first-degree relative with breast cancer – but 93% of women said breast density was a smaller risk.
Dense breast tissue refers to breasts composed of more glandular and fibrous tissue than fatty tissue. It is a normal and common finding present in about half of women who undergo a mammogram.
The researchers also interviewed 61 participants who reported being informed about their breast density and asked what they believe contributes to breast cancer and how they could reduce their risk. While most women rightly noted that breast density could mask tumors on mammograms, few women felt that breast density could be a risk factor for breast cancer.
About a third of women thought there was nothing they could do to reduce their breast cancer risk, although there are several ways to reduce the risk, including maintaining a healthy, active lifestyle and minimizing alcohol consumption.
Breast density changes throughout 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 risk of breast cancer increases with the degree of breast density; however, experts aren’t sure why this is true.
“One hypothesis has been that women with more dense breast tissue also have higher, greater levels of estrogen, circulating estrogen, which contributes to both breast density and risk of developing breast cancer,” said Dr. Harold Burstein, a breast specialist. oncologist at the Dana-Farber Cancer Institute who was not involved in the study. “Another hypothesis is that there is something about the tissue itself that makes it denser, which somehow predisposes to the development of breast cancer. We don’t really know which one explains the observation.”
Thirty-eight states currently require women to receive written notification of their breast density and potential breast cancer risk after mammography; however, studies have shown that many women find this information confusing.
“Even though women are usually notified in writing when they get a report after a mammogram that says, ‘You have increased breast density,’ it’s just right there at the bottom of the report. I’m not sure anyone explains them, especially in person or orally, whatever 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 need to better educate not only the general public of women, but also the general public of primary care providers who are ordering screening mammograms,” she added.
Current screening guidelines recommend that women with an average risk of breast cancer undergo breast cancer screening every one to two years between the ages of 50 and 74, with the option of starting at age 40.
Because women with dense breast tissue are believed to have a higher than average risk of cancer, the study authors suggest that women with high breast density may benefit from additional screening such as breast MRI or breast ultrasound, which can detect cancers that mammograms are missed. Currently, coverage of additional screening after the first mammogram varies by state and insurance policy.
The authors warn that “additional screening may not only lead to increased cancer detection rates, but may also result in more false positives and recalls.” They say clinicians should use risk assessment tools when discussing trade-offs associated with additional screening.
“Usually it is a conversation between the patient, the clinical team and the radiologist. And it’s going to be influenced by the history, by whether there’s anything else of interest on the mammogram, by the patient’s family history. So those are the things that we often discuss with patients who are in situations like that,” Burstein said.
Breast cancer screening recommendations vary between medical organizations, and experts say women at higher risk due to breast density should discuss with their doctors which screening method and frequency is most appropriate.
“I think it’s very, very important that everyone understands – and these are the doctors, the nurses, the women themselves – that screening is not a standard recommendation. We can’t just make one general recommendation to the entire population because individual women have different risk levels of getting breast cancer,” Oratz said.
For nearly a third of women with dense breast tissue who 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 target several modifiable factors. Breastfeeding may reduce the risk. On the other hand, the use of hormone replacement therapy increases the risk of breast cancer,” says 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 drugs, such as tamoxifen, that can be given to people at significantly increased risk that can reduce the risk 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 a woman is uncomfortable about something happening in her breast, if she has discomfort, notices a change in the breast, bring that to your doctor’s attention and have it evaluated and have it’s not somebody just brushing you off,” Oratz said.