In recent years, women with dense breast tissue have been encouraged more and more to make more frequent check-ups than just the annual mammogram, as studies revealed dense breast tissue represent an increased chance of developing breast cancer.
However, a new study shows that not only is the risk of cancer not at high as previously believed, but also that it does not apply to all women who have dense breasts.
The results were published in the Annals of Internal Medicine by Dr. Karla Kerlikowske, professor of epidemiology and biostatistics at the University of California, San Francisco in collaboration with her colleagues.
More than 365,000 women aged 40 to 74 years old, participated in the study, totaling to roughly 831,000 mammograms. The follow-up period of 12 months after the initial mammogram revealed information about how many women had developed breast cancer.
Results showed that breast density is not an accurate indicator of higher risk of cancer. Researchers tried various models and criteria in order to predict which women had a risk of developing cancer; they included either just breast density on its own, or in combination with other factors – family history of breast cancer, age, race, and recent breast biopsy.
Determining if a woman has dense breast tissue is done based on a mammogram, but approximately 42 percent of the dense-breasted women participating in the study appeared to have very low risk of developing cancer.
Furthermore, more screenings and having an ultrasound or an MRI proved to be helpful only in 24 percent of the cases with higher risk. Therefore, only 12 percent of women who get mammograms – including patients with dense breast tissue – would be in need of getting further screening.
The gap between these results and the current practice is huge, as all women who have dense breasts are urged to receive more frequent screenings. There are currently 22 states commissioning physicians to ask patients with dense tissue breasts to consider additional screening.
Even though a federal law on the same issue is undergoing reviews at the time, people are wondering if it is indeed necessary, since only a few insurers are willing to cover the extra screening.
Almost half of the women who get mammograms are told they have dense breast tissue, and according to Kerlikowske, requiring extra screenings for so many is neither cost-effective nor realistic.
As the study proved, it’s not impossible to identify the cases of dense breasts that are more likely to develop cancer; doctors need to be taking all risk factors under consideration, such as age and medical family history.
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