Hormone Therapy for Metastatic Breast Cancer

What is hormone therapy?

Estrogen and progesterone are female hormones produced in the body. Some breast cancer cells need estrogen and/or progesterone to grow.

When these hormones attach to special proteins called hormone receptors, the cancer cells with these receptors grow.

Hormone therapy drugs work by preventing the cancer cells from getting the estrogen they need to grow.

Hormone therapies may also be called endocrine therapies. The endocrine system in the body makes hormones.

Hormone therapy and metastatic breast cancer treatment

Hormone therapy is usually the first treatment for hormone receptor-positive metastatic breast cancers.

For women, the choice of hormone therapy depends on menopausal status and any past hormone treatment for early breast cancer [4].

Learn more about emerging areas in hormone therapy for metastatic breast cancer.

Learn more about treatment for metastatic breast cancer.

Hormone therapy for premenopausal women

For premenopausal women with metastatic breast cancer, hormone therapy almost always begins with ovarian suppression and either an aromatase inhibitor, tamoxifen or other hormone therapy drug.

Ovarian suppression lowers hormone levels in the body so the tumor can’t get the estrogen it needs to grow. This may involve surgery to remove the ovaries (oophorectomy) or, more often, drugs (such as goserelin or leuprolide) to stop the ovaries from producing hormones.

Combining ovarian suppression and a hormone therapy drug (such as an aromatase inhibitor or tamoxifen) improves survival over either treatment alone [5].

If breast cancer progressed during past treatment with a hormone therapy drug, the same hormone therapy drug may not be an option for treatment.

Learn more about ovarian suppression.

Learn more about tamoxifen.

Learn more about aromatase inhibitors.

Hormone therapy for postmenopausal women

After menopause, hormone therapy for women with metastatic breast cancer can be an aromatase inhibitor, tamoxifen, fulvestrant or other hormone therapy drug.

If the first hormone therapy stops working and the cancer starts to grow again, a second hormone therapy can be used. If the second drug stops working, another can be tried.

Ovarian suppression isn’t helpful for postmenopausal women because their ovaries have already stopped producing large amounts of estrogen. (Postmenopausal women still make a small amount of estrogen in fat tissue and the adrenal glands.)

Learn more about tamoxifen.

Learn more about aromatase inhibitors.

Hormone therapy drugs for metastatic breast cancer

Some hormone therapy drugs are pills and some are given by injection under the skin (a shot).

Figure 5.8: Hormone therapies for metastatic breast cancer


Brand name

Used in pre- or postmenopausal women?

Injection or pill?

























Megestrol acetate


Pre- and postmenopausal




Pre- and postmenopausal






To learn more about a specific hormone therapy, visit the National Institutes of Health’s Medline Plus website.

Monitoring metastatic breast cancer

You’ll be monitored (checked) regularly to see if the cancer is responding to treatment. If it’s no longer working, or if the side effects are not manageable, your health care provider will change your treatment.

When hormone therapy stops working

At some point, even though it may be years away, hormone therapy almost always stops working. At this point, chemotherapy may be recommended.

Learn more about how metastatic breast cancer is monitored.

Side effects of hormone therapies

Different hormone therapies have different side effects.

Learn about the side effects of tamoxifen.

Learn about the side effects of aromatase inhibitors.

Learn about the side effects of ovarian suppression.

Clinical trials

Clinical trials offer the chance to try new treatments and possibly benefit from them.

Consider joining a clinical trial when your oncologist is considering changing treatments, before starting a new treatment or when there are limited treatment options.

Susan G. Komen® Breast Care Helpline

If you or a loved one needs information or resources about clinical trials, call the Komen Breast Care Helpline at 1-877 GO KOMEN (1-877- 465- 6636) or email clinicaltrialinfo@komen.org.

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Metastatic Trial Search

The Metastatic Trial Search is a web-based clinical trial matching tool that can help you find clinical trials that fit your needs.

Learn more about clinical trials for people with metastatic breast cancer.

Prescription drug assistance

The cost of drug therapies for metastatic breast cancer can quickly become a financial burden for you and your family.

Medicare and many insurance companies offer prescription drug plans. One may already be included in your policy, or you may be able to buy an extra plan for prescriptions.

Some drugs are off-patent and may have a generic form. Generic drugs cost less than the name brands but are just as effective.

You may also qualify for programs that help with drug costs or offer low-cost or free prescriptions.

Learn more about insurance plans and prescription drug assistance programs.

Learn more about other financial assistance programs.

Komen Financial Assistance Program

Susan G. Komen® created the Komen Financial Assistance Program to help those struggling with the costs of breast cancer treatment by providing financial assistance to eligible individuals.

Funding is available for eligible individuals undergoing breast cancer treatment at any stage or living with metastatic breast cancer (stage IV).

To learn more about this program and other helpful resources, call the Komen Breast Care Helpline at 1-877 GO KOMEN (1-877-465-6636) or email helpline@komen.org.

Se habla español.

Susan G. Komen®‘s position on fairness in oral cancer drug coverage

Insurance coverage of oral cancer drugs

Cancer medications given by vein (through an IV) or injection (under the skin or into a muscle) are usually covered under a health insurance plan’s medical benefit. However, cancer medications that are pills (oral cancer drugs) are usually covered under a health insurance plan’s prescription drug benefit.

As a result, people often find themselves facing high out-of-pocket costs when filling prescriptions for oral cancer drugs. Sometimes these costs can be thousands of dollars a month.

The impact of high cost-sharing

High prescription drug costs and the resulting out-of-pocket burden on patients are a barrier to care. They can prevent people from getting the medications prescribed by their health care providers.

No one should be forced to get less appropriate treatment because an insurer gives more coverage for IV and injectable drugs than pills.

Efforts to increase fairness in drug coverage

Komen supports state and federal efforts to require insurers to provide the same or better coverage for oral cancer drugs as they do for IV and injectable cancer drugs. This would help make sure patients have access to affordable, appropriate treatment.

Become a Komen Advocacy Insider

Sign up to be a Komen Advocacy Insider and get informed when action is needed on drug coverage issues at the state or national level.


  • If you or a loved one needs more information about breast health or breast cancer, contact the Komen Breast Care Helpline at 1-877 GO KOMEN (1-877-465-6636) or email helpline@komen.org. All calls are answered by a trained specialist or oncology social worker, Monday through Friday from 9:00 a.m. to 10:00 p.m. ET. Se habla español.
  • Komen Patient Navigators can help guide you through the health care system as you go through a breast cancer diagnosis. They can help to remove barriers to high-quality breast care. For example, they can help you with insurance, local resources, communication with health care providers and more. Call the Komen Breast Care Helpline at 1-877 GO KOMEN (1-877-465-6636) or email helpline@komen.org to learn more about our Patient Navigator program, including eligibility.
  • We offer an online support community through our closed Komen Metastatic Breast Cancer group. The Facebook group provides a place where those living with metastatic breast cancer, and those who love them, can find support, friendship and information. Visit Facebook, search for Komen Metastatic Breast Cancer (Stage IV) Group and request to join the closed group.
  • Our free MBC Impact Series provides people living with metastatic breast cancer and their loved ones a safe, collaborative space to gather information related to MBC and discover practical resources to help make decisions for improved physical and emotional health. To learn more and register visit www.komen.org/mbcseries.
  • Our podcast series Real Pink covers many relevant topics for people living with metastatic breast cancer and caregivers.
  • Our fact sheets, booklets and other education materials offer additional information.

Komen Perspectives

Read our perspective on metastatic breast cancer.*

Learn More

*Please note, the information provided within Komen Perspectives articles is only current as of the date of posting. Therefore, some information may be out of date.

Updated 06/30/22


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