Hormone Therapy for Breast Cancer

Hormone therapy (also called endocrine therapy) is a common treatment for hormone receptor-positive (HR+) breast cancer. In HR+ breast cancer, cancerous tumors rely on the hormones estrogen and progesterone to grow. Your body makes these hormones. An HR+ tumor may be estrogen receptor-positive (ER+), progesterone receptor-positive (PR+) or both. Most breast cancers in the United States are HR+. They account for 3 out of every 4 cases.

Hormone therapy treats these breast cancers by lowering hormone levels or blocking hormones that help cancer cells grow. Oncologists use hormone therapy:

• After breast cancer surgery: Hormone therapy can reduce the risk of a tumor growing back.
• Before breast cancer surgery: It can shrink the tumor so it’s easier to remove.
• To treat advanced cancers: It helps some people with incurable disease live longer.
• To reduce your cancer risk: This treatment may help prevent some HR+ breast cancers. Your healthcare provider may suggest it if your lifetime risk of breast cancer is high.

What are the types of hormone therapy for breast cancer?

Hormone therapies for breast cancer include drug types that block cancer cells’ access to estrogen and progesterone. Others cause your body to make less estrogen. Hormone therapy types include:

• Aromatase inhibitors: If you have ER+ breast cancer and you’ve gone through menopause, your healthcare providers may use this type of hormone therapy. Anastrozole (Arimidex^®), exemestane (Aromasin^®) and letrozole (Femara^®) are commonly used aromatase inhibitors.
• Ovarian function suppression: Your provider may prescribe medications like goserelin (Zoladex^®, Zoladex 3-Month^®) and leuprolide (Lupron^®) if you develop ER+ breast cancer before menopause. This treatment slows cancer growth by keeping your ovaries from making estrogen.
• Selective estrogen receptor modulators (SERMs): Healthcare providers use SERMs to treat ER+ breast cancer. SERMs like tamoxifen (Nolvadex^®, Soltamox^®) and raloxifene (Evista^®) are effective treatments for some types of breast cancer.
• Selective estrogen receptor down regulators (SERDs): These treatments keep estrogen from connecting to cancer cells. Examples are fulvestrant (Faslodex^®), elacestrant (Orserdu^®), imlunestrant (Inluriyo^®) and camizestrant (Etcamah^®).
• Proteolysis targeting chimeras (PROTACs): This is a new treatment that triggers the destruction of multiple estrogen receptors in a continuous loop. Vepdegestrant (Veppanu^®) is an example.

What happens during treatment?

With most types of hormone therapy (endocrine therapy) for breast cancer, you take a pill each day. For others, you may need regular injections at your healthcare provider’s office.

The most effective hormone treatment for HR+ breast cancer varies based on whether you get diagnosed before or after menopause. This is because the places where estrogen gets made in your body change based on your menopause status. Before menopause, it’s made in your ovaries. After menopause, it’s made in tissue like fat and muscle.

• After menopause: The most common treatment is an aromatase inhibitor or an aromatase inhibitor followed by tamoxifen.
• Before menopause: The most common treatment is tamoxifen or ovarian function suppression with an aromatase inhibitor.

Depending on your situation, you may also need other cancer treatments, like:

• Chemotherapy: To kill cancer cells throughout your body
• Radiation therapy: To destroy tumors (usually when surgery isn’t an option)
• Targeted therapy: To block proteins that cause cancer to grow

Your provider will explain each part of your treatment plan, so you understand why it’s best for you.

How long will I need this treatment?

Most people need hormone therapy for breast cancer for at least five years after surgery. You may need it for longer if there’s a high risk of the cancer coming back.

Your healthcare provider will let you know whether they recommend hormone therapy beyond five years. Even if you’re not high risk, there may be benefits to staying on it for longer.

How successful is hormone therapy for breast cancer?

It’s highly successful. In the early 1990s, groundbreaking breast cancer research showed that women with breast cancer who were treated with tamoxifen (a type of hormone therapy) lived longer than those who weren’t. This study and others like it helped hormone therapies become the standard in treating HR+ breast cancers.

Hormone therapy for breast cancer:

• Helps both men and women with breast cancer live longer
• Reduces the chance of breast cancer coming back
• Reduces the risk of a new breast cancer forming

Is there anything I can do to make this treatment easier on me?

There are pros and cons with any treatment. The pros of hormone therapy — including saving lives — make this treatment worth it for most people. But there are also cons in the form of side effects. They vary from person to person and based on the drug type. Side effects include:

• Fatigue
• Nausea
• Hot flashes
• Night sweats
• Joint and muscle pain or stiffness
• Changes in your periods
• Loss of interest in sex
• Vaginal dryness
• Mood swings
• Weaker bones (an increased risk of osteoporosis)

Let your provider know right away if you need help managing side effects. For instance, they may help you change your eating habits to reduce symptoms like nausea and fatigue. They may prescribe meds that can ease symptoms. Another option may be to switch drug types. Your provider can guide you.

When should I call my healthcare provider?

Reach out to your provider to let them know about new side effects. Contact them if you notice changes that may mean the cancer has come back (recurred).

Signs to look out for include:

• A new lump in your breast
• Pain in your chest, belly or bones
• Trouble breathing
• Headache that persists

Which is better for breast cancer: chemotherapy or hormone therapy?

It depends on your diagnosis. But healthcare providers recommend hormone therapy for most people with HR+ breast cancers.

Chemotherapy destroys cancer cells throughout your body, whether or not they have hormone receptors. Hormone therapy works on cancer cells that have hormone receptors. It starves cancer cells of the hormones they need to grow.

What if I don’t want hormone therapy?

If you have breast cancer, you have many treatment options. Your oncologist recommends treatment plans based on what they know about the kind of breast cancer you have, your overall health and your preferences.

Take some time to study your options. Talk to your oncologist and weigh the risks and benefits of hormone therapy.

What not to eat with hormone positive breast cancer?

With breast cancer, it’s important to eat foods that provide the nutrients you need to stay strong. This means avoiding processed foods that contain lots of sugar or fat. This can be hard to do. It may help to think instead about what’s good to eat, like fruits, veggies, whole grains and lean protein.

Some research shows that eating moderate amounts of foods with phytoestrogens may help reduce the risk of recurrence in ER+ breast cancers. Both soy and green tea are rich in phytoestrogens.

But consuming a single ingredient isn’t as important as building healthy eating patterns into your daily life. Ask your healthcare provider about what a healthy meal plan looks like for you.

Is hormone therapy for cancer the same as hormone therapy for menopause?

No, it’s not. Hormone therapy for menopause boosts hormone levels to relieve menopause symptoms. Hormone therapy for cancer is different because you don’t treat breast cancer with hormones. Instead, hormone (endocrine) therapy blocks cancer cells’ access to the hormones in your body they use to grow.