Is There a Link Between HRT and Breast Cancer?

10/19/2024

Curious about hormone replacement therapy and breast cancer? Here’s what you need to know to make an informed decision about your health.

By Mandy Greenberg, MD, Breast Surgery, Nuvance Health

Navigating menopause can feel overwhelming when you’re faced with decisions like whether to try hormone replacement therapy (HRT). While HRT can help manage symptoms like hot flashes and vaginal dryness, many women are concerned about how it might affect their breast cancer risk.

Let’s explore what you need to know about HRT and breast cancer risk so you can feel confident discussing your options with your doctor.

What is hormone replacement therapy?

Hormone replacement therapy helps replenish the hormones your body stops producing during perimenopause and menopause. For most women, the decrease in estrogen and progesterone levels causes symptoms, including hot flashes, night sweats, mood swings and vaginal dryness. These symptoms can range from mild to severe, as your body adjusts to the hormonal changes in this new phase of life.

Your doctor may suggest HRT if your symptoms affect your quality of life. For example, menopause symptoms like hot flashes can disturb your sleep and make it difficult for you to do all the things that matter to you during the day. Sometimes, hot flashes and brain fog from menopause can make it difficult to function well during the day. While HRT can be very effective at reducing these symptoms, it’s important to understand its potential risks, especially when it comes to breast cancer.

How does HRT work?

HRT supplements the hormones your body is no longer producing. There are two main hormones involved in HRT:

Estrogen is the main hormone that decreases during menopause, which causes most of the symptoms.

Progesterone is used in combination with estrogen for women who still have their uterus. Progesterone helps protect the lining of the uterus (endometrium) from the effects of estrogen, which can lead to an increased risk of uterine cancer.

The goal of HRT is to restore hormonal balance and provide relief from menopause symptoms. There are several different ways to take HRT, including pills, patches, creams and gels. Your doctor will help you choose the best method based on your symptoms, health history and personal preferences.

Related content: Breast health facts for every age

What are the different types of HRT?

There are two main types of hormone replacement therapy:

Estrogen-only HRT: This is typically prescribed for women who have had a hysterectomy (surgical removal of the uterus). Since there’s no risk of uterine cancer, you don’t need to take progesterone. Estrogen-only HRT is associated with a lower risk of breast cancer compared to combined HRT.

Combined HRT (estrogen and progesterone): Women who still have their uterus need to take progesterone along with estrogen to protect against uterine cancer. However, this combination therapy is the type most linked to an increased risk of breast cancer, especially with long-term use.

Bioidentical HRT: These hormones are chemically identical to your body’s natural production. Some women prefer this option because it’s considered more “natural,” but it’s important to know that bioidentical HRT comes in both FDA-approved and compounded forms, with compounded forms being less regulated.

Does HRT affect breast cancer risk?

One of the biggest concerns women have about HRT is whether it increases the risk of breast cancer. The answer isn’t the same for everyone because it depends on your individual health, breast cancer risk, stage of life and the type of HRT you’re using. Let’s break it down:

HRT for women at average risk of breast cancer

What does it mean to be at average risk for breast cancer? It means you don’t have a family history, genetic mutation like BRCA1 (breast cancer 1) or BRCA2 (breast cancer 2) or other significant risk factors. For women at average risk, studies show that combined HRT (estrogen and progesterone) can slightly increase the risk of breast cancer after five or more years of continuous use.

Studies show estrogen-only therapy, on the other hand, does not increase breast cancer risk. However, it can increase the risk of endometrial cancer and ovarian cancer. It’s very important to speak with your doctor about your personal and family health history to determine the HRT that may be best for you.

Related content: Breast cancer risk factors, explained

HRT for women at high risk of breast cancer

If you’re at higher risk for breast cancer, using HRT, particularly combined HRT (estrogen and progesterone), may further increase your breast cancer risk. That’s why it’s especially important for high-risk women to have a detailed discussion with their doctor about whether HRT is the right choice or if there are safer alternatives for managing menopausal symptoms.

If you’re at high risk of breast cancer, you may have one or more of the following risk factors:

A family history of breast cancer, particularly a first-degree relative (parent, sibling or child).

Inherited genetic mutations, such as BRCA1, BRCA2 or ATM (ataxia telangiectasia mutated).

A personal history of other breast conditions like atypical hyperplasia or lobular carcinoma in situ (LCIS).

Ethnicity, because Ashkenazi Jewish women have a higher risk for breast cancer.

Reproductive health, because never giving birth, having your first child after age 30 and not breastfeeding can increase breast cancer risk. Starting your period before age 12 and going through menopause after age 55 can also increase your risk because of lifetime exposure to estrogen.

Lifestyle, because excess weight, an unhealthy diet, no exercise, alcohol and smoking can increase breast cancer risk.

Talk with your gynecologist or primary can provider about your breast cancer risk. They may suggest you see a genetics counselor for testing and a breast surgeon for a risk assessment. At Nuvance Health, breast cancer risk assessments are also calculated when you have breast imaging, such as a mammogram.

Find a primary care provider near me.

HRT and breast cancer risk for those who’ve had breast cancer

If you’ve had breast cancer, the question of whether HRT is safe becomes even more complicated. In general, we don’t recommend systemic (full-body) HRT for breast cancer survivors, especially if you had hormone-receptor-positive breast cancer. Estrogen could potentially fuel the growth of any remaining cancer cells, increasing the risk of recurrence. There are exceptions to this rule, but it’s a decision that needs to be made very carefully between you and your healthcare team.

How do I know if HRT is right for me?

Deciding whether HRT is right for you involves considering both the benefits and the risks. On the plus side, HRT is effective at relieving menopausal symptoms like hot flashes, night sweats and vaginal dryness. It can also help prevent bone loss, which reduces the risk of osteoporosis and fractures as you age.

Related content: Your bones on menopause

However, there are potential side effects to be aware of, including an increased risk of breast cancer (with combined HRT), blood clots, stroke and heart disease. These risks vary depending on your health and family history, so it’s important to have an open conversation with your doctor about what makes sense.

Are there alternatives to HRT?

If you’re hesitant about HRT or if you’re at increased risk for breast cancer, there are several non-hormonal options available to help manage menopausal symptoms.

Non-hormonal treatment options for menopause

Some medications that are typically used for other conditions can help with menopausal symptoms. For example, certain antidepressants (like SSRIs) have been shown to reduce hot flashes. Gabapentin, a medication often used for nerve pain, can also provide relief. These options don’t come with the same cancer risks as HRT, making them an alternative for some women.

Localized HRT

Menopause can cause vaginal dryness, making intercourse uncomfortable. Vaginal estrogen in the form of creams or tablets can help. Localized HRT does not increase breast cancer risk because, unlike systemic HRT, it stays in the area where it is applied. Talk with your gynecologist about vaginal estrogen options to relieve this common symptom of menopause.

Lifestyle changes to manage menopausal symptoms

Lifestyle changes can also make a big difference in managing menopause. Regular exercise, a healthy diet and stress reduction techniques like yoga or meditation can help ease symptoms. Quitting smoking, cutting back on alcohol and maintaining a healthy weight are all positive steps that can improve your overall health and help reduce menopausal symptoms.

Natural remedies for menopause symptoms

Some women find relief through natural remedies like black cohosh, soy or flaxseed. While research on these treatments is mixed, they are considered safe for most women. Acupuncture may also help relieve menopause symptoms. It’s important to talk to your doctor before trying any new supplements, especially if you’re concerned about breast cancer.

What should I do if I have questions about HRT?

If you’re unsure whether HRT is the right choice for you, don’t hesitate to reach out to your gynecologist or primary care provider. If you have breast cancer, your breast surgeon or medical oncologist are terrific resources for information about HRT. Any of these specialists can review your medical history, help you assess your risk for breast cancer or a recurrence and guide you toward the best treatment options for your individual needs. Every woman’s situation is unique, and what works for one person might not be the best choice for another.

The bottom line: Hormone replacement therapy can help manage the symptoms of menopause, but it’s important to be aware of the potential risks, particularly when it comes to breast cancer. If you're at average risk of breast cancer, combined HRT can increase your risk after long-term use, while estrogen-only therapy poses a lower risk. For women at high risk or those who’ve had breast cancer, non-hormonal alternatives may be safer. Discuss your options with your doctor to make the best decision for your health and well-being.

Is there a link between hormone replacement therapy and breast cancer?