Hormones, hormone receptors and 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 therapies slow or stop the growth of hormone receptor-positive tumors by preventing the cancer cells from getting the hormones they need to grow.
Hormone therapies may also be called endocrine therapies. The endocrine system in the body makes hormones.
Hormone receptor status and hormone therapy
All tumors are checked for hormone receptors. A pathologist determines the hormone receptor status by testing the tumor tissue removed during a biopsy.
- Hormone receptor-positive (estrogen receptor-positive/progesterone receptor-positive) tumors express hormone receptors. This means they have a lot of hormone receptors.
- Hormone receptor-negative (estrogen receptor-negative/progesterone receptor-negative) tumors do not express hormone receptors. This means they have few or no hormone receptors.
Hormone therapies are only used to treat hormone receptor-positive breast cancers. Most breast cancers are hormone receptor-positive.
Learn more about hormone receptor status.
Hormone therapy and metastatic breast cancer treatment
Learn more about hormone therapies used to treat metastatic breast cancer.
How do hormone therapies work?
Hormone therapy drugs slow or stop the growth of hormone receptor-positive breast cancers in a few ways:
- Some hormone therapies, such as tamoxifen, attach to the hormone receptor in the cancer cell and block estrogen from attaching to the receptor.
- Others, such as aromatase inhibitors and ovarian suppression, lower the level of estrogen in the body so the cancer cells can’t get the estrogen they need to grow.
Benefits of hormone therapies in early and locally advanced breast cancer treatment
For hormone receptor-positive early and locally advanced breast cancers, treatment with the hormone therapies tamoxifen and/or an aromatase inhibitor lowers the risk of [87-89]:
- Breast cancer recurrence (a return of breast cancer)
- Breast cancer in the opposite breast
- Death from breast cancer
Premenopausal women who get ovarian suppression plus tamoxifen or an aromatase inhibitor may lower these risks more than premenopausal women who get tamoxifen alone .
Learn more about tamoxifen.
Learn more about aromatase inhibitors.
Learn more about ovarian suppression.
Hormone therapy options for early and locally advanced breast cancer
For women with hormone receptor-positive breast cancer, hormone therapy drug options depend on whether or not they have gone through menopause.
Men with hormone receptor-positive breast cancer most often take tamoxifen.
Hormone therapy options for early and locally advanced breast cancer
Premenopausal (before menopause) women
Postmenopausal (after menopause) women
Tamoxifen plus ovarian suppression
Aromatase inhibitor plus ovarian suppression
Aromatase inhibitor plus androgen deprivation therapy
Hormone therapy and CDK4/6 inhibitors
CDK4/6 inhibitors are drugs designed to interrupt the growth of cancer cells. CDK4/6 inhibitors include abemaciclib (Verzenio), palbociclib (Ibrance) and ribociclib (Kisqali).
Early and locally advanced breast cancer
The CDK4/6 inhibitor abemaciclib is used in combination with hormone therapy to treat some hormone receptor-positive early breast cancers at high risk of recurrence.
Learn more about abemaciclib and early breast cancer treatment.
Metastatic breast cancer
The CDK4/6 inhibitors abemaciclib, palbociclib and ribociclib are used in combination with hormone therapy to treat some hormone receptor-positive metastatic breast cancers.
Learn more about CDK4/6 inhibitors and metastatic breast cancer treatment.
Hormone therapy versus menopausal hormone therapy
Hormone therapy for breast cancer treatment is different than menopausal hormone therapy (MHT).
- Hormone therapies used in breast cancer treatment act as “anti-hormone” or “anti-estrogen” therapies. They block hormone actions or lower hormone levels in the body.
- MHT is used to increase hormone levels in the body to treat menopausal symptoms.
MHT increases the risk of breast cancer. It’s not usually recommended for women with breast cancer. For other women, it’s only recommended at the lowest dose, for the shortest time needed, to ease menopausal symptoms .
MHT is also called postmenopausal hormone use or hormone replacement therapy (HRT).
Learn more about MHT and breast cancer risk.
Learn more about MHT and breast cancer survival.
Learn about other ways to ease menopausal symptoms.
Hormone therapy drugs for early and locally advanced breast cancer
Hormone therapies for early and locally advanced breast cancer
Used in pre- or postmenopausal women?
Injection or pill?
Pre- and postmenopausal
Ovarian suppression drugs
Learn about hormone therapy drugs for metastatic breast cancer.
To learn more about a specific hormone therapy, visit the National Institutes of Health’s Medline Plus website.
Although the exact treatment for breast cancer varies from person to person, evidence-based guidelines help ensure high-quality care. These guidelines are based on the latest research and agreement among experts.
In addition, the National Cancer Institute (NCI) has treatment overviews.
Talk with your health care team about which treatment guidelines they use.
After you get a recommended treatment plan from your health care team, study your treatment options. Together with your health care team, make thoughtful, informed decisions that are best for you. Each treatment option has risks and benefits to consider along with your own values and lifestyle.
Importance of following your breast cancer treatment plan
Breast cancer treatment is most effective when all parts of the treatment plan are followed as prescribed.
Prescription drug assistance
Hormone therapy drug costs 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.
Most hormone therapies are pills, so they’re covered under your health insurance plan’s prescription drug benefit rather than the plan’s medical benefit. This means there are usually out-of-pocket costs, which can add up over time.
You may qualify for programs that help with drug costs or offer low-cost or free prescriptions.
Tamoxifen and aromatase inhibitors (anastrozole, exemestane and letrozole) all have generic forms. Generic drugs cost less than name brand drugs but are just as effective.
Many cancer centers have patient financial counselors who can discuss insurance and cost coverage with you.
Learn 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 4).
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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.
Research is ongoing to improve all areas of treatment for breast cancer.
New therapies are being studied in clinical trials. The results of these studies will decide whether these therapies become part of the standard of care.
After discussing the benefits and risks with your health care provider, we encourage you to consider joining a clinical trial.
Susan G. Komen® Breast Care Helpline
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BreastCancerTrials.org in collaboration with Komen offers a custom matching service to help find clinical trials that fit your needs.
Learn more about clinical trials.
Read our perspective on clinical trials.*
Susan G. Komen® Support Resources
*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.