Does hormone replacement therapy increase cancer risk?

Hot flashes. Insomnia. Mood changes.

If you've experienced menopause symptoms, you can probably relate to the feeling of wanting them to, well, stop.

Hormone replacement therapies (HRT) are hormonal medications that can help reduce menopause symptoms. While these therapies offer welcome symptom relief for many people, they have also been associated with side effects, including increased breast cancer risk.

Here, I’ll share more about hormone replacement therapy, its link to cancer risk and how to decide if it is right for you. 

What is hormone replacement therapy?

After menopause, the amount of estrogen and other hormones in a woman’s body decreases. Hormone replacement therapies provide the body with more of certain hormones. Many HRTs use a combination of two types of hormones: estrogen and progesterone.

HRTs can help manage menopause symptoms, such as:

• Hot flashes 
• Vaginal dryness
• Sleep disturbances
• Mood changes
• Depression 
• Osteopenia and osteoporosis (bone density loss)
• Joint aches and pains

HRT use is decided on a case-by-case basis. This means your doctor will consider your age, your health history and your symptoms to decide if hormone replacement therapy is right for you and how long it should be used.

In general, hormone replacement therapy for menopause can be used by women going through early menopause. It can also be used to help with the transition from pre-menopause to post-menopause. It should not be taken indefinitely.

HRT formats

Many different types of hormone replacement therapy for menopause have been approved by the Food and Drug Administration (FDA). These HRTs come in formats such as:

• Pills
• Patches 
• Gels
• Injections
• Creams
• Sprays 
• Vaginal rings and inserts

Each HRT has pros and cons. For example, local HRTs, such as vaginal creams, tend to have less systemic absorption of the hormones compared to pills or injections.

Talk to your doctor to decide what type of HRT is best for you. Your doctor may also consider non-hormonal approaches to relieve symptoms if appropriate.

Is HRT linked to cancer risk?

Yes. In general, when you take hormone replacement therapy, you're taking estrogen and progesterone. These hormones are linked to several types of cancer, including breast cancer and endometrial cancer.

Hormone replacement therapy’s cancer risk depends on many factors, such as the combination of hormones used (estrogen alone or estrogen plus progesterone), the format and how long someone takes it for. Like many other cancer risk factors, someone’s cancer risk from using HRT increases the longer they use it. 

The Women's Health Initiative (WHI) examined the risk of breast cancer in women ages 50 to 59 who took oral HRT with estrogen and progestin (a human-made version of progesterone) for five years. The study followed up with these women and found that there were three additional cases of invasive breast cancer per 1,000 women.

Yet, while estrogen and progesterone can increase your risk for cancer, they can also have benefits. For example, estrogen can alleviate menopause symptoms and help with bone health, skin health, heart health and sexual health. 

There are many factors to consider when deciding whether to use hormone replacement therapy. It really depends on the person. That’s why choosing to use hormone replacement therapy is a decision each person should make with their care team.

Does hormone replacement therapy have any other side effects? 

Yes. HRT also has side effects. These may include an increased risk of:

• Stroke
  
• Pulmonary embolism

In general, it's recommended that patients stop taking HRT by age 60 so the risk of these side effects goes down.

The risk of these conditions may decrease when you stop taking hormone replacement therapy. 

Is hormone replacement therapy the same as hormone therapy?

No. While hormone replacement therapy and hormone therapy sound similar, they work in opposite ways.

Hormone therapy, or endocrine therapy, reduces or blocks certain hormones, such as estrogen, that the body creates and uses. In other words, it is really anti-estrogen or anti-hormone therapy. Hormone therapy can be used to treat some cancers, such as certain types of breast cancer, that rely on hormones to spread.

Examples of hormone therapy used in breast cancer include tamoxifen and aromatase inhibitors such as anastrozole, letrozole or exemestane.

Can cancer patients use HRT for menopause symptoms? 

Hormone replacement therapy is not recommended for women who have or had breast cancer with a hormone-receptor positive subtype, such as estrogen-receptor (ER)-positive breast cancer.

There isn’t a lot of data on using hormone replacement therapy in women who have or had other types of breast cancer, including triple negative or ER-negative breast cancer. However, in general, if somebody has breast cancer or had a history of breast cancer, we prefer that they do not receive hormone replacement therapy.

If you have or had another type of cancer, taking HRT has the same risk for you as it does for people without cancer. 

Are there other ways to treat menopause symptoms besides hormone replacement therapy?

Hormone replacement therapy isn’t the right choice for everyone. There are non-hormonal medications and other interventions you can use to treat menopause symptoms. 

Non-hormonal medications

Medicine that can treat menopause symptoms without hormones include selective serotonin reuptake inhibitors (SSRIs) and gabapentin. A new FDA-approved drug called fezolinetant can also treat menopause symptoms, but its effectiveness in treating breast cancer survivors, specifically, has not been tested. 

Other interventions 

Exercise, yoga and acupuncture may provide relief from menopause symptoms.

How can someone decide if hormone replacement therapy is right for them? 

As a breast medical oncologist, I work with each patient to weigh the risks and benefits of each option. In some cases, it may make sense for a patient to use an HRT such as vaginal estrogen cream to help with severe vaginal dryness. In other cases, it doesn’t. It's not a black and white situation. 

If you are experiencing menopause symptoms, speak with your care team to decide if hormone replacement therapy is right for you. Your care team can also offer suggestions for other ways to reduce your menopause symptoms.

Request an appointment at MD Anderson online or call 1-877-632-6789.