Dubai, United Arab Emirates (CNN) — Dense breast tissue has been linked to a fourfold increased risk of breast cancer. However, a new study indicates that few women consider breast density to be an important risk factor.
The study, published in JAMA Network Open, included 1,858 women ages 40 to 76 between 2019 and 2020 who reported having had a recent mammogram, had no family history of breast cancer, and had heard of breast cancer. breast density.
The women were asked to compare the risk of breast density against five other risk factors for breast cancer: having a first-degree relative with breast cancer, being overweight or obese, drinking more than one alcoholic drink per day, not having children, or having had a previous breast biopsy. .
“When compared with other known breast cancer risks, perhaps more well-known, women did not realize that breast density was a significant risk factor,” said study author Laura Pedler, a researcher at the Dartmouth Institute for Health Policy and Clinical Practice.
For example, the authors reported that dense breast tissue was associated with a 1.2- to 4-fold increased risk of breast cancer compared to a 2-fold higher risk of a first-degree relative developing breast cancer, but 93% of women said they had a lower risk of breast density factor. .
High-density breast tissue indicated a breast composed of more fibrous and glandular tissue than adipose tissue. This is a normal finding and is common in about half of all women who have a mammogram.
The researchers also interviewed 61 participants who reported their breast density, and were asked if they believed it contributed to their development of breast cancer, and how they could reduce their risk. While the majority of women correctly noted that breast density may mask tumors on mammograms, a few women felt that this could be a risk factor for breast cancer.
Nearly a third of the women thought there was nothing they could do to reduce their risk of breast cancer, although there are many ways to reduce the risk, including maintaining a healthy, active lifestyle and reducing alcohol consumption.
High density breast tissue
Breast density changes throughout a woman’s life, and is generally higher in women who are younger, have a lower body weight, or are pregnant, breast-feeding, or taking hormone replacement therapy.
The risk of breast cancer increases with the degree of breast density. However, experts are not sure why this is true.
“One hypothesis was that women who have denser breast tissue also have higher and greater levels of estrogen, and estrogens, which contribute to both breast density,” said Dr. Harold Burstein, a breast oncologist at Dana-Farber Cancer Institute who was not involved in the study. and the risk of breast cancer.”
“Another hypothesis is that there is something about the tissues themselves that makes them denser and somehow predisposes to the development of breast cancer. We don’t really know which one explains the observation.”
Currently, 38 states require that women receive written notification about their breast density and breast cancer risk after a mammogram. However, studies have shown that many women find this information ambiguous.
“Although women are usually notified in writing when they receive a report after a mammogram that they have ‘enlarged breasts,'” Dr. Ruth Ortz, a breast oncologist at New York University’s Perlmutter Cancer Center who was not involved in the study, said, at the bottom of the report.
“I think what we’ve learned from this study is that we have to do a better job not only of doing public education for women, but for general primary care health care providers who ask these women for mammograms.”
Screening does not fit all recommendations.
Current screening guidelines recommend that women at average risk of breast cancer have breast cancer screening annually or every two years between ages 50 and 74, with the option to start at age 40.
Because women with dense breast tissue are considered to have a higher-than-average risk of developing cancer, the study authors noted that women with dense breast tissue may benefit from complementary screening such as a breast MRI or breast ultrasound, which may help with breast cancer. It may detect cancers that are not detected on a mammogram.
However, the authors cautioned, “Supplementary screening not only increases cancer detection rates, but may also lead to more false-positive results and repeat appointments.” They recommend that clinicians use risk assessment tools when discussing trade-offs associated with supplementary screening.
“It’s usually a discussion between the patient and the clinical team, the radiologist. It will be influenced by the patient’s family history, whether there is anything else of concern on the mammogram,” Boerstein explained.
Oratz believes that “it is important that everyone, doctors, nurses and women, understand that screening does not fit all recommendations. We cannot make just one general recommendation for everyone because women have different levels of breast cancer risk.”
Reducing the risk of breast cancer
For about a third of women with dense breast tissue, there is nothing you can do to prevent breast cancer, but experts say there are some steps you can take to reduce your risk of developing breast cancer.
According to Dr. Puneet Singh, a breast oncology specialist at MD Anderson Cancer Center who was not involved in the study, “Maintaining an active and healthy lifestyle and reducing alcohol consumption addresses many modifiable factors. Breastfeeding can also reduce the risk. On the other hand, the use of hormone replacement therapy increases the risk of breast cancer.
The researchers added that there are approved drugs, such as tamoxifen, that could be given to those at very increased risk, which could reduce the chances of developing breast cancer by about half.
Finally, breast cancer doctors said that in addition to proper screening, knowing your risk factors and advocating for yourself can be powerful tools for preventing and detecting breast cancer.
