HRT & Breast Cancer: What Women Need to Know

Key Takeaways

• HRT is not one-size-fits-all. The type of hormoneA chemical substance produced in the body that controls and regulates the activity of certain cells or organs. therapy, timing, duration, and a woman’s personal and family history all influence its potential benefits and risks.
• The relationship between HRT and breast cancer is complex. Breast cancer risk varies depending on the type of HRT used, with estrogen-progestogen combinations carrying different risks than estrogen-only therapy.
• Individual breast cancer risk matters. Women with a BRCA mutation, strong family history, or a personal history of breast cancer should have an individualized discussion with their healthcare provider before considering HRT.
• The benefits of HRT can be significant. For women experiencing disruptive menopausal symptoms, HRT may improve quality of life, and non-hormonal treatments are also available. Treatment should be initiated within 1-2 years of median age of menopauseThe end of a woman’s menstrual cycles, defined as 12 consecutive months of no menstrual periods., which in the US is fifty-one, before the age of sixty, or within 10 years of menopause.
• Talk with your healthcare provider. Because research and recommendations continue to evolve, HRT decisions should be based on an individual assessment of symptoms, medical history, and potential risks and benefits.

Hormone replacement therapy (HRT) and its relationship to breast cancer has been a controversial topic for many years. A common treatment for menopausal women, HRT was discontinued by many after the publication of a prominent government-backed 2002 study linking HRT to breast cancer (1), but since then, multiples studies have indicated relative safety of these products and resulted in the Food and Drug Administration’s (FDA) removal of the black box warning in February 2026 (2). The warnings which were removed were regarding breast cancer, cardiovascular disease, and dementia. The current FDA approved indications for HRT include treatment of menopausal symptoms: vasomotor (hot flashes), genitourinary (vaginal dryness, painful intercourse), and osteoporosis.

What Is Hormone Replacement Therapy (HRT)?

Hormone replacement therapy (HRT) is also referred to as menopausal hormone therapy (MHT) or postmenopausal hormone therapy (PMHT, PHT). It is sometimes misleadingly referred to as estrogenA female sex hormone that is primarily produced by the ovaries. Its primary function is to regulate the menstrual cycle and assist in the production of secondary sex characteristics such as breasts. It may even play a role in the production of cancer cells in the breast tissue. replacement therapy, although therapy regimens are individually prescribed based on patient’s clinical history, symptoms, and the desired goals of treatment.  Thus, they can contain any combination of estrogen, progesteroneA hormone that stimulates the uterus to prepare for pregnancy, produced mainly by the ovaries. Progesterone may play a role in certain breast cancers., and testosterone hormones. HRT has been used to treat menopause symptoms like hot flashes, sleep disturbances, palpitations, anxiety, vaginal dryness and atrophyTissue in the body wastes away or breaks down., bone loss, skin aging, decreased muscle mass, and sexual dysfunction.

Is HRT Linked To Breast Cancer?

In 1993, the Women’s Health Initiative (WHI), conducted by the National Institute of Health, was one of the largest studies of its kind, following over 160,000 post-menopausal women over a 15-year period. The intent was to study rates of cancer, cardiovascular disease, and osteoporosis for women on HRT and those receiving placebo (medication without active ingredients). The study found a breast cancer risk increase of 24% for women who took a combination of estrogen-progesterone (3). This amounts to an increase in the actual chance of getting breast cancer to 15.5% compared to average risk of 12.5% (typically cited as “1 in 8”). To put this in perspective, this risk is equivalent to 8-9 additional breast cancers for every 1,000 women, if the medication is taken for five or more years. The study also showed a 20% decreased breast cancer risk for women who had previously undergone hysterectomies and were prescribed estrogen-only HRT. The results garnered intense media attention, a drastic reduction in HRT prescriptions, and a decrease in breast cancer diagnoses in the following year, a decrease which, in a 2007 New England Journal of Medicine paper, was attributed to the drop in HRT use. (4)

However, since 2002, additional and longer follow-up studies have continued to explore how HRT and breast cancer are related. A follow up study of WHI outcomes revealed that women receiving estrogen and progesterone combination experienced increased risk of breast cancer and a non-significantly increased risk of heart disease, with lower risk of hip fractures and endometrial cancer. Women on estrogen only preparation had increased risk of stroke and blood clots but a decreased risk of hip fracture and a non-significantly decreased risk of invasive breast cancer. Further, the results suggested adverse impact of older age and the time of initiation of treatment since the onset of menopause on the risks of HRT use. (5) A 20 year follow up to WHI confirmed increased risk of breast cancer for the combination HRT and a significantly lower risk of breast cancer for women using only estrogen replacement, with no increased risk of death caused by breast cancer in either group. (6) A (8) A more recent publication summarizing the risks and benefits of HRT acknowledges potential risks of HRT which can be managed by the timing of initiation of treatment, its duration and appropriate monitoring. (9)

Based on these and other recent studies examining hormone type, patient age and length of therapy use, the medical community has re-evaluated guidelines on HRT use on a more individual basis. The severity of the patient’s symptoms and her personal goals, and accounting for her specific risk of breast cancer play an important role in shared decision-making. The unique situation each patient faces is an important consideration in the type and timing of HRT and therefore should be discussed with your physician.

HRT for the Average Woman

Health and quality of life are the driving forces for clinical decision-making. When menopause symptoms are disruptive, HRT should be recommended and considered. Treatment should be initiated within 1-2 years of median age of menopause, which in the US is fifty-one, before the age of sixty, or within 10 years of menopause. (10) Treatment of specific symptoms, such as vaginal HRT for vaginal dryness is advisable. For women who have had a hysterectomy, the lowest dose estrogen-only HRT is recommended for a period of 5 years. Longer duration of treatment is associated with an increased risk of complications, but these risks should be considered along with the severity of symptoms. For women with an intact uterus, estrogen-progesterone HRT combination is advised, also at the lowest dose, with length of treatment also of limited duration. Other alternatives include estrogen with progesterone eluting intrauterine devices to decrease stimulation of the endometrial lining and subsequent abnormalities. 

HRT for BRCA-Positive & Other High-Risk Women

Women who have a high risk of breast cancer, for instance those who have a BRCA1A gene which, when damaged or mutated, can put a person at a greater risk of developing breast and/or ovarian cancer. or BRCA2A gene which, when damaged or mutated, may put a woman at a greater risk of developing breast and/or ovarian cancer. This gene is also thought to raise the risk for breast cancer in men. mutation or those with a strong family history, should avoid hormone replacement therapy, if possible, except for those who have undergone risk-reducing salpingo-oophorectomy surgery (RRSO, removal of their tubes and ovariesThe female reproductive organs in which ova or eggs and hormones are produced.), resulting in premature menopause. While alternatives to HRT, such as non-hormonal methods, can be considered first, these women are at risk of increased risk of premature death related to estrogen deprivation. HRT doses result in hormone levels which are significantly lower than natural production of hormones if the ovaries were left intact. HRT should be discussed, particularly for patients with BRCA1 deleterious mutation, as they are likely to undergo RRSO prior to the age of menopause. (11)For patients who do not wish to take HRT, treatment of hot flashes may be effectively addressed by administration of a selective serotonin-uptake inhibitor, acupuncture, exercise, or layered clothing, or for vaginal dryness, an over-the-counter lubricant could relieve symptoms.

Vaginal laser therapies, which are not FDA-approved to treat menopause-related vaginal issues (12), nor are they approved by the American College of Obstetricians and Gynecologists (13), should be avoided. Care should be exercised with the use of natural supplements. They have variable ingredients and strength and lack safety data. Some have negative side effects on blood clotting or may interfere with other medications a patient may be taking.

If all non-HRT therapies have not been effective, HRT may still be utilized. Currently recommended doses of hormones, as mentioned previously, contain much lower levels of hormone preparation than those studied in 2002 by WHI, and bioidentical rather than synthetic options are available. Although long-term outcomes are not known, it is anticipated that risk of breast cancer may be less. As with the women at average risk of breast cancer, the lowest dose of medication for the shortest amount of time is best. Many patients will take an HRT for 6-18 months and are then successfully able to taper off.

HRT for Breast Cancer Survivors

Breast cancer survivors may experience menopause early as a result of the treatment. Some may also test positive for BRCA or other high-risk mutations or have a strong family history of breast cancer. Therefore, treatment with HRT after breast cancer diagnosis should be initiated only after consultation with the patient’s oncologistA doctor who specializes in the diagnosis and treatment of cancer. and a comprehensive review of risks and benefits.

Increasingly, newly diagnosed breast cancer patients are young and premenopausal, and have significant survivorship issues that need to be addressed. There can be a profound effect of estrogen deficiency in these patients that negatively affect bone health and genital and urinary organ conditions, which often need to be addressed.

Vaginal estrogen products, approved by the American College of Obstetricians and Gynecologists (ACOG) in 2017, can be used (15). According to their statement, which was reaffirmed in 2020, vaginal estrogen products have shown no increased risk of breast cancer recurrenceThe reappearance of the disease after it has been treated. In breast cancer, recurrence following primary breast cancer can be local (in the same place), regional (in surrounding tissue) or metastatic (in some other part of the body). among women currently undergoing treatment or among those with a history of breast cancer who use vaginal estrogen (8). Many studies have been done demonstrating that serum levels of estrogen in the blood are very low to non-existent.

The Bottom Line

Controversy regarding hormone replacement therapy continues, but as a result of recent FDA removal of black box warning, and as an improved quality of life is increasingly desired by patients, demand for HRT is now at an all-time high Due to the evolving science in this area of medicine, consultation with one’s  physician, following a review of the  specific symptoms, personal and family medical history, decision should be reach through shared decision-making to arrive at a treatment plan which minimizes symptoms and the risks of any therapy. Many options are available to establish a therapy plan that is in each patient’s best interest.