What is the most likely risk factor for developing breast cancer ? As part of a new study published this January 23, 2023 in the journal JAMA Network Open1,858 women aged 40 to 76 who had recently had a mammogram, had no history of breast cancer, and had ever heard of breast density were asked about the risk of breast density in relation to five other factors such as having a first-degree relative with the disease, being overweight, drinking alcohol, not having children, and having had a breast biopsy earlier.
Among all these factors, the women surveyed seemed to greatly underestimate the impact of breast density on the occurrence of breast cancer compared to other risk factors. “Although breast density is associated with a 1.2 to four times increased risk of breast cancer, few women perceive breast density as a personal risk factor.”, says the study. They are even 93% say breast density is only a lower risk.
They actually perceive their family history more as a risk factor, even though the risk is “only” twice as high in the case of a first-degree relative with the disease. Finally, about a third of them also believe that they can do nothing to reduce their risk of breast cancer, even though there are several ways to do this, including through a healthy and active lifestyle as well as than a reduction in the consumption of alcohol and tobacco.
Breast density changes throughout life
But what is dense breast tissue? A so-called dense chest refers to their higher composition of fibrous glandular tissue than fatty tissue. There is nothing abnormal about this observation: a dense chest can be detected in nearly half of women (about 40%) having a mammogram.
A woman’s breast density changes over her lifetime. In particular, it can be higher in younger women, those who have a lower body weight, who are pregnant or breastfeeding and finally those who take hormone replacement therapy.
But why does the risk increase with the degree of breast density? “One hypothesis is that women who have denser breast tissue have higher levels of estrogen, which contributes to both breast density and the risk of developing breast cancer.”says Dr. Harold Burstein, breast oncologist, at CNN.
While the widespread breast cancer screening targets women aged 50 to 74 in France by inviting them to have mammograms every two years (apart from major risk factors, the authors of the study suggest that women with high breast density can benefit from additional screening (MRI or breast ultrasound), which may detect missed cancers during mammograms and alert on the need to raise awareness about this subject among the women concerned: better knowing their risk factors would make it possible to detect these cancers earlier.
Sources:
- Perceptions of Breast Cancer Risks Among Women Receiving Mammograph Screening, JAMA Network Open, January 23, 2023
- Many women underestimate breast density as a risk factor for breast cancer, study shows, CNN, January 23, 2023