HRT Doesn’t Seem To Raise Risk of Breast Cancer Recurrence in Certain Women
Overall, neither systemic nor vaginal hormone replacement therapy (HRT) increased the risk of breast cancer recurrence (the cancer coming back) in women diagnosed with early-stage, estrogen receptor-positive disease. Still, using vaginal HRT slightly increased recurrence risk in women who received an aromatase inhibitor, according to a Danish study.
The research was published online on July 20, 2022, by the Journal of the National Cancer Institute. Read “Systemic or Vaginal Hormone Therapy After Early Breast Cancer: A Danish Observational Cohort Study.”
Aromatase inhibitors are a type of hormonal therapy that treat estrogen receptor-positive and progesterone receptor-positive breast cancer.
There are three aromatase inhibitors that treat breast cancer:
Arimidex (chemical name: anastrozole)
Aromasin (chemical name: exemestane)
Femara (chemical name: letrozole)
Tamoxifen is another type of hormonal therapy that treats estrogen receptor-positive and progesterone receptor-positive breast cancer.
Many post-menopausal women take HRT to ease symptoms of menopause, such as hot flashes, night sweats, and fatigue.
There are two main types of HRT:
Combination HRT contains the hormones estrogen and progesterone.
Estrogen-only HRT contains only estrogen.
There are several ways to take or use HRT:
Systemic HRT usually contains a higher dose of estrogen and comes in many forms, including pills, skin patches, creams, gels, sprays, or vaginal rings. Systemic means the medicines travel through the bloodstream to all parts of the body.
Topical (local) HRT contains a lower-dose of estrogen and comes in the form of creams, tablets, or low-dose vaginal rings. These medicines aren’t as readily absorbed into your bloodstream and mostly stay in the vaginal tissue.
Systemic HRT effectively treats many symptoms of menopause, including hot flashes and night sweats. Topical HRT only works on vaginal symptoms, such as dryness and discomfort during sex.
National and international guidelines say that women who have been diagnosed with breast cancer should not take HRT of any type. This is because the hormones in HRT can cause hormone receptor-positive breast cancers to develop and grow.
Still, only a few small studies have looked at HRT use in women with a personal history of breast cancer. In this study, the researchers wanted to see if there were links between HRT use and recurrence in women who had been diagnosed with early-stage, estrogen receptor-positive breast cancer.
About the study
The study included 8,461 Danish women who received treatment for early-stage, estrogen receptor-positive breast cancer between 1997 and 2004:
2,007 women received tamoxifen for five years after surgery
403 women received an aromatase inhibitor for five years after surgery
2,939 women received tamoxifen and an aromatase inhibitor in sequence for five years after surgery
3,112 women received no hormonal therapy after surgery
The women’s ages ranged from 35 to 95 years.
1,957 women used vaginal HRT
133 women used both vaginal HRT and systemic HRT or used only systemic HRT
6,371 women didn’t use HRT
Women who didn’t use HRT were more likely to be:
diagnosed with a larger breast cancer
diagnosed with node-positive breast cancer (which means cancer was found in the lymph nodes)
The researchers followed half the women for more than 9.8 years and half for shorter periods of time.
During follow-up, 1,333 women had a breast cancer recurrence. Of the women who had a recurrence:
111 used vaginal HRT
16 used systemic HRT
1,206 didn’t use HRT
The researchers looked at the risk of breast cancer recurrence by the type of HRT the women used, as well as by the type of hormonal therapy the women received:
Women who used vaginal HRT had about the same risk of recurrence as women who didn’t use HRT.
Women who used systemic HRT had a slightly higher risk of recurrence — 0.05% higher — than women who didn’t use HRT.
Women who took an aromatase inhibitor and used vaginal HRT had a 39% higher risk of recurrence than women who didn’t use HRT.
Of all the women in the study, 3,370 died before Jan. 1, 2017. Of the women who died:
497 women used vaginal HRT
47 women used systemic HRT
2,826 women didn’t use HRT
The researchers’ analysis found that using HRT didn’t increase the risk of dying.
“In post-menopausal women treated for early-stage, [estrogen receptor-positive breast cancer], use of [vaginal HRT] or [systemic HRT] was not associated with increased risk of recurrence or mortality,” the authors concluded.
“[T]he results of this highly clinically relevant study by Cold and colleagues suggest that patients who are taking tamoxifen and experience severe genitourinary symptoms of menopause may safely initiate vaginal estrogen, as [it] does not appear to statistically significantly increase risk for breast cancer recurrence or survival,” wrote Elizabeth J. Cathcart-Rake, MD, and Kathryn J. Ruddy, MD, MPH, both of the Mayo Clinic’s Department of Oncology, in an editorial accompanying the study. “Patients who are taking aromatase inhibitors should try alternative strategies for management of genitourinary symptoms because [vaginal HRT] will likely increase their risk for breast cancer recurrence.”
What this means for you
If you’ve received treatment for early-stage, estrogen receptor-positive breast cancer, this study offers important information.
The study suggests that, if you take tamoxifen, you can safely use vaginal HRT to ease vaginal dryness, overactive bladder, pain during sex, and other reproductive- or urinary-related issues associated with menopause. Still, it’s important to remember that HRT usually doesn’t help ease hot flashes and night sweats.
If you take an aromatase inhibitor, it’s a good idea to talk to your doctor about other ways of managing menopausal symptoms. Research suggests that lifestyle changes, complementary and alternative medicine techniques, and non-hormonal medicines may help.
Lifestyle changes include:
identifying and avoiding hot-flash triggers, such as stress, alcohol, caffeine, and smoking
maintaining a healthy weight
exercising daily to reduce stress
Complementary and alternative medicine techniques include:
Non-hormonal medicines include:
antidepressants such as Effexor (chemical name: venlafaxine) and Celexa (chemical name: citalopram)
high blood pressure medicines such as clonidine
anti-seizure medicines such as gabapentin and Lyrica (chemical name: pregabalin)
overactive bladder medicines such as oxybutynin
Learn more about Treating Menopausal Symptoms.
Learn more about Using HRT (Hormone Replacement Therapy).
Written by: Jamie DePolo, senior editor
— Last updated on August 1, 2022, 8:48 PM