Menopausal Hormone Therapy and Cancer Risk

Menopausal hormone therapy (MHT), also called hormone replacement therapy (HRT) or post-menopausal hormone therapy (PHT), can help ease symptoms of menopause, like hot flashes, night sweats, and vaginal dryness.

Menopause occurs when the ovaries start making fewer hormones and menstrual periods cease. It can occur naturally from aging or from certain medicines or surgeries used to treat medical conditions, including cancer.

While MHT can improve your quality of life, it may also affect your risk of getting certain cancers. Knowing more about your risk can help you make informed decisions with your health care team.

Types of hormone treatments for menopause and their risks

MHT comes in different forms and works by replacing the hormones your ovaries no longer make. These include estrogen and progesterone.

For some people, estrogen alone is the best option. For others, estrogen plus progesterone is better. The risks depend on which hormones are used, how they’re given and for how long, and whether a person still has their uterus.

Overall, MHT is likely a safe option for healthy people with bothersome menopausal symptoms, who are younger than age 60 or within 10 years of the start of menopause, and don’t have certain health problems such as breast cancer, heart disease, a history of stroke or blood clots, or liver disease.

Estrogen as MHT

There are 3 main types of estrogen in the body:

• Estradiol is made mainly in the ovaries.
• Estrone is made mainly in fat tissue.
• Estriol is made mainly by the placenta during pregnancy.

Lab-made (synthetic) forms of these hormones can be given as medicines that replace the estrogen lost after menopause.

Estrogen is the most effective hormone treatment for menopause symptoms. The type used most often is estradiol. It can be given as:

• A patch, gel, or spray that you apply to your skin
• A pill that you take by mouth
• A ring, cream, or tablets that you put inside your vagina
• Injections into your skin (not used commonly in the US)

Another option for estrogen is conjugated equine estrogens (CEEs) that you take as a pill by mouth or a cream put into your vagina. Both estradiol and CEEs can be given alone or in combination with progesterone.

When estrogen is taken, it’s usually given on a set schedule without any breaks in therapy.

Estrogen therapy and cancer risk

Treating menopausal symptoms with estrogen alone is known as estrogen therapy (ET).

ET has been shown to affect the risk for certain cancers. The degree of risk depends on how long it is taken and the person’s age and health. Low-dose vaginal estrogen raises estrogen levels much less than pills or patches and it’s not clear whether it changes cancer risk at this time.

Progesterone as MHT

Before menopause, progesterone is made mainly by the ovaries. It’s also made in smaller amounts by the adrenal glands and the placenta during pregnancy.

Medicines that act like progesterone are called progestins. The different types of progestins available include:

• Medroxyprogesterone acetate (MPA)
• Norethindrone acetate
• Micronized progesterone
• Levonorgestrel

Progestins used for MHT may be given as a pill (most common), as a patch, or as an intrauterine device (IUD) put into the vagina, depending on the type used.

Some preparations contain both an estrogen and a progestin. When both hormones are used together, it’s called estrogen-progestin therapy (EPT).

When using EPT to help with symptoms of menopause, it can be given 2 ways:

• Continuous EPT: Estrogen and progestin are taken each day at the same dose. Many prefer this option because it rarely causes menstrual-like bleeding.
• Sequential (cyclical) EPT: Estrogen and progestin are taken on a set schedule, with progestin used only on certain days. This approach may more closely match normal hormone patterns and lowers the amount of progestin that you’re exposed to. But it can produce menstrual-like bleeding, although it may happen less often than once a month.

Estrogen-progestin therapy (EPT) and cancer risk

EPT also affects cancer risk in different ways based on your age and how long it’s taken.

Testosterone as MHT

Sometimes the hormone testosterone is talked about to help with some menopause symptoms. But, this isn’t approved by the US Food and Drug Administration (FDA) and more study is needed.

Risks of vaginal estrogen versus systemic (whole body) hormones

MHT can be given in ways that either:

• Affect the whole body (systemic therapy)
• Act mainly where they are applied (local therapy)

Each has certain risks and benefits to consider.

Deciding whether to use menopausal hormone therapy (MHT)

The decision to use hormone therapy after menopause, like ET or EPT, should be made by you and your doctor after weighing the possible risks and benefits. If you decide to use it, it should be in a way that matches your symptoms, health history, and personal goals.

Some may choose to use the lowest effective dose for as short a time as possible, while others may choose to use hormone therapy for longer periods. Things to think about include:

• How bothersome your menopausal symptoms are
• Your baseline risk of breast, endometrial, ovarian, and other types of cancer, and how much this might be affected by hormone therapy
• The risks of other serious conditions that might be affected by hormone therapy, like heart disease, stroke, serious blood clots, and effects on the brain
• The type and dose of the hormones the doctor recommends
• What other medicines might be options to treat menopausal symptoms instead

The American Cancer Society has no position or guidelines regarding menopausal hormone therapy.

Follow-up while on MHT

As with any medicine, regular follow-up with your doctor if you’re on MHT is important so they can see how well the treatment is working, monitor for side effects, and revisit the risks and benefits over time.

You should report any vaginal bleeding that happens after menopause to your doctors right away because it may be a symptom of endometrial cancer. People who take EPT don’t have a higher risk of endometrial cancer, but they can still get it.

People using ET vaginal cream, rings, or tablets should talk to their doctors about follow-up and the possible need for progestin treatment.

You should follow the American Cancer Society guidelines for the early detection of cancer, especially those for breast cancer. These guidelines can be found in Breast Cancer Early Detection.

Non-hormonal medicines to help with menopause symptoms

If you cannot or choose not to use MHT, there are non-hormonal medicines that may be used to help manage menopause symptoms.

Some antidepressants taken at low doses can reduce hot flashes and night sweats. These medicines don’t treat depression when used this way. Instead, they target the brain chemicals involved in temperature control.

Other prescription options include medicines originally used for seizures or nerve pain, which can also help lessen hot flashes, especially at night. Newer therapies include medicines that target the brain pathways that trigger hot flashes.

Possible side effects

Non-hormonal medicines may cause side effects such as nausea, dizziness, dry mouth, or sleep changes, and they don’t work the same way for everyone. They also don’t help with vaginal dryness or protect against bone loss.

Because of this, it’s important to talk with your doctor about your symptoms, your overall health, and any other medicines you take. Together, you can decide whether a non-hormonal option may be a good choice for you.

Herbs and supplements during menopause

Many over-the-counter “natural” or herbal products are promoted as helpful with menopausal symptoms. These include vitamins, soy-based products, and herbs like black cohosh and red clover. These products are sold as dietary supplements, not medicines.

Most haven’t been evaluated by the FDA to make sure they work or are safe. Some have been tested in small, short-term clinical trials, but we don’t know much about their long-term safety. It’s also hard to apply results from one version or dose of a supplement to others that weren’t tested and may be different.

Be cautious of products with “secret formulas” or hormone-like ingredients. Some imported natural supplements have been found to contain actual drugs, including ones banned in the US. You have the right to know exactly what you’re taking and what risks or interactions it may have.

Most single herbs used for menopausal symptoms are likely to have a low risk of harm for most women, but some can interact with other drugs or cause unexpected side effects. You should discuss any herbs or supplements you’re considering with your doctor before taking them.

Well-controlled research is needed to know if these products work, how well they work compared to the current hormone therapies now in use, and if they are safe. Learn more about dietary supplements and safety.

Bioidentical hormones

The word bioidentical means a hormone has the same chemical structure as one that the body makes naturally. However, this term is also sometimes used to describe combinations of hormones that are custom made by compounding pharmacies, often with doses adjusted based on blood or saliva hormone tests.

Compounded bioidentical hormones are often marketed as being more natural, which can make them seem safer than other forms of hormone therapy used for menopause.

But these products aren’t tested for quality or safety by the FDA. There are also no long-term studies showing they’re safer or cause fewer side effects than other types. For this reason, they should be assumed to have at least the same health risks as any other type of MHT.