A new study has confirmed growing concerns that women who undergo hormone therapy that includes progestin and estrogen have an increased risk of developing and dying from breast cancer, especially if they begin their therapy at the start of menopause.
As part of the study, researchers followed roughly 42,000 post-menopausal women for an average of just over 11 years. Of the women involved in the study, over 25,000 did not undergo hormone therapy, while over 16,000 took progestin and estrogen, a process also referred to as combination hormone therapy. In this particular study, researches did not include women who underwent estrogen-only therapy, which is commonly used by women that have undergone a hysterectomy.
Concluding the follow-up period of the study, over 2,200 women had received a breast cancer diagnosis. When compared to participants who did not undergo therapy, women who took combined therapy had a higher chance to develop breast cancer, according to researchers who led the study at the Los Angeles Biomedical Research Institute.
The results of the study were published in the March issues of the Journal of the National Cancer Institute.
A Reason for Concern
While other studies have found a potential link between hormone therapy and the development of breast cancer, this latest study was the first to determine that women had a greater risk when undergoing hormone therapy near the beginning of menopause. Researches concluded that women who began hormone therapy within a few months of menopause were three times more likely to develop breast cancer than women who started therapy 10 years following the advent of menopause.
As part of the latest study, researchers examined the results from the Women’s Health Initiative observational study. Researchers then compared those results with findings from the randomized clinical trials organized by the Women’s Health Initiative, which assigned women to different treatment methods.
The WHI included an observational study and four clinical trials. Participants in each group were all between the ages of 50 to 79 and had already past menopause.
Researchers started this latest study to resolve what was viewed as unanswered questions regarding the risks of hormone therapy to women starting menopause. In the WHI trial, approximately only one-third of the participants were in the 50s when the study began. Since that also marks the typical age in which menopause begins, roughly two-thirds of the women who participated in the trial were in their 60s or older, and had begun undergoing hormone therapy several years following menopause.
Researchers then set about to determine whether the link between combined hormone therapy and breast cancer risk was influenced by the use of hormones at an earlier time. Researchers found that not only was the risk of breast cancer higher, but it also grew even larger if a woman began to take hormones towards the beginning of menopause. The study speculates that women who begin hormone therapy towards the beginning of menopause have elevated levels of estrogen that could become hazardously high when combined with early hormone therapy.
A Change in Treatment
While additional research has shown that early hormone therapy may actually improve heart health, researchers caution that these benefits need to be weighed against the increased risk of breast cancer to determine any true value. However, even if doctors no longer recommended hormone therapy, women must still make their own personal decision about whether to seek treatment to deal with symptoms such as night sweats and hot flashes. Some women may find the risk acceptable if their symptoms progress for the worse, but researchers hope that women with milder, manageable symptoms give the risks of hormone therapy a long, hard look before starting treatment.