For many women, the answer is yes. Hormone replacement therapy (HRT), now more commonly called menopausal hormone therapy (MHT), is an effective treatment for troublesome symptoms of menopause and is considered safe for most healthy women in their 50s or within 10 years of menopause.
However, HRT is not suitable for everyone. The benefits and risks depend on factors including your age, when menopause occurred, your medical history, whether you still have a uterus, and the type, dose and route of hormone therapy used.
As a breast surgeon, I have sometimes seen patients newly diagnosed with breast cancer who have been taking HRT. Understandably, two questions often arise:
- Did HRT cause my breast cancer?
- Do I need to stop HRT?
The answers are more nuanced than a simple yes or no.
What are the benefits of HRT?
Menopause can cause symptoms including:
- hot flushes and night sweats
- sleep disturbance
- vaginal dryness and discomfort
- pain during sex
- changes in sexual function
- mood symptoms.
HRT is the most effective treatment for menopausal hot flushes and night sweats. It can also improve other menopause-related symptoms and helps prevent the bone loss and fractures associated with osteoporosis.
For most healthy women who start HRT before the age of 60 or within 10 years of menopause, the overall balance of benefits and risks is generally favourable.
The decision to use HRT should nevertheless be individualised. Not every woman needs it, and the safest type of treatment will differ according to her circumstances.
What is the evidence relating to HRT and breast cancer risk?
Breast cancer risk naturally increases with age and is influenced by many factors, including genetics, alcohol consumption, body weight, reproductive history and hormonal exposure.
HRT can also affect breast cancer risk, but the size of this effect depends importantly on the type of HRT being used and how long it is used for.
It is therefore misleading to talk about the breast cancer risk of “HRT” as though all forms carry the same risk.
Combined HRT (oestrogen + progestogen)
Women who still have their uterus generally need a progestogen as well as oestrogen. This protects the lining of the uterus (endometrium) from the increased risk of endometrial cancer caused by using systemic oestrogen alone.
Combined oestrogen-progestogen HRT is associated with an increased risk of breast cancer. The risk generally increases with duration of use.
It is important to put this into perspective. For women aged 50–59, Australian menopause guidance estimates approximately:
- 9 additional breast cancers per 10,000 women per year with recent combined HRT use for 1–5 years; and
- 15 additional cases per 10,000 women per year with recent combined HRT use for 5 years or more,
compared with women who have never used HRT.
The individual’s underlying breast cancer risk also matters. A relative increase in risk will have a different absolute effect in someone whose baseline risk is low compared with someone whose baseline risk is already high.
Breast cancer risk decreases after combined HRT is stopped, although evidence varies as to how quickly any additional risk disappears.
There is also emerging evidence that breast cancer risk may differ between particular progestogens and treatment regimens, but these differences are not yet sufficiently certain to regard any combined systemic HRT regimen as completely risk-free.
Oestrogen-only HRT
The breast cancer evidence is different for oestrogen-only HRT.
High-quality randomised evidence has not demonstrated an increased breast cancer risk with oestrogen-only therapy, and some studies have suggested a lower risk. Observational studies have produced somewhat different results, particularly with prolonged use, so the evidence is not entirely uniform.
Importantly, systemic oestrogen alone is generally only appropriate for women who have had a hysterectomy. In a woman who still has her uterus, using systemic oestrogen without adequate progestogen protection can increase the risk of endometrial cancer.
Synthetic steroid hormone therapy
Synthetic steroids with oestrogenic, progestogenic and androgenic effects can be used to treat menopausal symptoms in some postmenopausal women, particularly when low libido or sexual function is a concern. It may also cause less breast tenderness and less unscheduled bleeding than combined MHT.
This type of treatment may increase the risk of stroke when started after the age of 60 and should therefore be used with caution in this age group. It should not be used by women with a history of breast cancer because evidence indicates an increased risk of breast cancer recurrence.
What about “bioidentical” or “natural” HRT?
The term bioidentical can be confusing.
Some regulated HRT products contain hormones, such as oestradiol and micronised progesterone, that are chemically identical to hormones produced by the human body. These are pharmaceutical products with standardised doses and quality controls.
This is different from compounded bioidentical hormone therapy, in which preparations are individually compounded by a pharmacy.
The Australasian Menopause Society does not recommend compounded bioidentical hormone therapy. These products have not been shown to be safer or more effective than approved HRT, and there may be concerns about consistency of dose, purity, effectiveness and safety.
“Natural” does not necessarily mean safer.
Does the way you take HRT affect the risks?
Yes. This is an important distinction.
Systemic oestrogen can be taken orally or absorbed through the skin using a patch or gel. While both routes can effectively treat menopausal symptoms, their risk profiles are not identical.
Oral oestrogen increases the risk of venous blood clots, such as deep vein thrombosis (DVT) and pulmonary embolism. Oestrogen delivered through the skin appears to have a lower risk of blood clots and is often preferred when a woman has risk factors for thrombosis.
Age, smoking, obesity, previous blood clots, cardiovascular health and other medical conditions also affect an individual’s risk.
HRT should therefore not simply be thought of as one medication with one set of risks. The hormone, dose and method of administration matter.
What about vaginal oestrogen?
Low-dose vaginal oestrogen is different from systemic HRT.
It is used primarily for the genitourinary syndrome of menopause (GSM), which can cause vaginal dryness, irritation, painful sex and urinary symptoms.
Only small amounts are absorbed into the bloodstream when vaginal oestrogen is used at recommended doses. Available evidence has not demonstrated an increased breast cancer risk with low-dose vaginal oestrogen, and it can generally be used long term.
Women who have previously had breast cancer require more individualised advice. Non-hormonal vaginal moisturisers and lubricants are usually considered first. If symptoms persist, vaginal oestrogen may sometimes be considered after discussion with the woman’s treating doctor or breast cancer specialist, particularly because the considerations can differ depending on treatments such as tamoxifen or aromatase inhibitors.
What about testosterone?
Testosterone is sometimes prescribed to postmenopausal women with hypoactive sexual desire disorder (HSDD) after other contributing factors have been assessed.
Evidence supports testosterone for this specific indication, but there is currently insufficient evidence to recommend testosterone for other menopausal symptoms such as low mood, fatigue or cognitive symptoms. Treatment requires appropriate dosing and monitoring, and long-term safety data are more limited than for conventional menopausal hormone therapy.
What are the other risks of HRT?
The risks depend on the woman’s age, medical history and the type of HRT prescribed.
Potential risks can include:
- Blood clots: particularly with oral oestrogen. Transdermal oestrogen delivered through a patch or gel appears to have a lower clotting risk.
- Stroke: absolute risk is low in healthy women under 60, but increases with age and underlying cardiovascular risk. Route and dose of oestrogen may also matter.
- Breast cancer: predominantly associated with combined oestrogen-progestogen therapy and increasing duration of use.
- Endometrial cancer: systemic oestrogen used without adequate progestogen protection increases this risk in women who still have their uterus.
- Gallbladder disease: oral oestrogen can increase the risk of gallbladder problems.
This is why choosing HRT involves more than deciding whether to take hormones. The type, dose and route should be selected according to the individual woman’s symptoms and health risks.
So, is HRT safe?
For most healthy women experiencing troublesome menopausal symptoms who are under 60 or within 10 years of menopause, HRT has a favourable benefit-risk profile when there are no contraindications.
HRT does not need to be routinely stopped after an arbitrary two- or five-year period. Treatment should instead be reviewed periodically, taking into account:
- whether symptoms are continuing
- the benefits the woman is receiving
- her age and health
- her personal risk factors
- the type and dose of HRT being used
- her own preferences.
Some women may appropriately use HRT for longer than five years after discussing the changing benefits and risks with their doctor.
Women who experience premature ovarian insufficiency or early menopause are a separate group. Unless there is a contraindication, hormone therapy is generally recommended until approximately the usual age of natural menopause because replacing hormones in these younger women has important benefits for bone and overall health.
Can you take HRT after breast cancer?
Systemic HRT is generally not recommended for women with a previous breast cancer, because of concern that hormonal treatment may increase the risk of recurrence.
Menopausal symptoms after breast cancer can often be treated using non-hormonal approaches. For persistent vaginal and urinary symptoms, low-dose vaginal oestrogen may sometimes be considered after non-hormonal treatments have been unsuccessful, following an individualised discussion with the woman’s GP, oncologist or breast cancer specialist.
Women currently undergoing treatment for breast cancer should discuss any hormonal treatment, including vaginal oestrogen and compounded hormonal products, with their treating team.
The bottom line
HRT is not inherently “good” or “bad”. For many women it is a safe and highly effective treatment for menopausal symptoms, particularly when started before age 60 or within 10 years of menopause.
Breast cancer risk is not the same for every type of HRT. Combined oestrogen-progestogen therapy is associated with a small increase in breast cancer risk that increases with duration of use, whereas the evidence for oestrogen-only therapy is substantially more reassuring.
The safest approach is to choose treatment according to your symptoms, medical history and individual risk factors, and to review it periodically with your doctor rather than applying a fixed time limit to HRT use.
Looking for dedicated menopause care? Doctors for Menopause — part of the Qoctor group — offers comprehensive $199 video consultations with GPs who have a particular interest in menopause care. → doctorsformenopause.com.au
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Medically reviewed by Dr Aifric Boylan
MB · BCH · BAO · MICGP · FRACGP · DRCOG · DCH
About Dr Aifric Boylan MB BCh BAO MICGP FRACGP DRCOG DCH Fellow of the Royal Australian College of General Practitioners, Dr Aifric Boylan is a general practitioner with more than 20 years' experience. She graduated in medicine from…
This health information has been clinically reviewed by an Australian doctor. Qoctor health pages are reviewed to support clear, evidence-informed guidance; they do not replace individual medical advice.
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