Does Hormone Replacement Therapy Lead to Breast Cancer?
What is HRT?
According to the Mayo Clinic, hormone replacement therapy is a medication that contains female hormones. You take the medication to replace the estrogen that your body stops making during menopause. Hormone therapy is most often used to treat common menopausal symptoms, including hot flashes and vaginal discomfort.
The Science Behind the Study
Aromatase inhibitors can have a variety of side effects, including genitourinary problems associated with menopause such as vaginal dryness, itchiness, burning, overactive bladder, and urinary incontinence. Although these symptoms may be alleviated by the use of vaginal estrogen therapy (VET) or menopausal hormone therapy (MHT), there are concerns the therapies can increase the risk of breast cancer recurrence and death following treatment.
A large Danish observational cohort study concluded neither VET or MHT is linked with an increased risk of recurrence or mortality. However, a subgroup analysis discovered a higher risk of recurrence in women undergoing VET with adjuvant aromatase inhibitors, but not a higher risk of mortality.
Study Methods
The study included 8,461 postmenopausal Danish women between the ages of 35 to 95 years old who had been diagnosed with early-stage invasive ER-positive breast cancer between 1997 and 2004. Chemotherapy had not been given to the women. The individuals were randomly assigned to receive either 5 years of tamoxifen or an aromatase inhibitor, or both treatments in a sequence.
The researchers determined prescription data on hormone therapy, VET, or MHT from Denmark’s national prescription registry.
What Are the Results?
Among the 8,461 women who did not receive VET or MHT before their breast cancer diagnosis, 1,957 and 133 used VET and MHT after their diagnosis. The median follow-up for recurrence was 9.8 years, and for mortality, it was 15.2 years.
“In postmenopausal women treated for early-stage ER-positive breast cancer, neither VET nor MHT was associated with increased risk of recurrence or mortality. A subgroup analysis revealed an increased risk of recurrence, but not mortality, in patients receiving VET with adjuvant aromatase inhibitors,” concluded the authors of the study.
For more on HRT and breast cancer, head to the American Cancer Society.
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