When are hormone therapies used?
Some breast cancer cells need estrogen and/or progesterone (female hormones produced in the body) to grow.
When these hormones attach to special proteins called hormone receptors, the cancer cells with these receptors grow.
- Breast cancers with many cells with hormone receptors are hormone receptor-positive (estrogen receptor-positive (ER-positive) and/or progesterone receptor-positive (PR-positive)).
- Breast cancers with few or no cells with hormone receptors are hormone receptor-negative (estrogen receptor-negative (ER-negative) and/or progesterone receptor-negative (PR-negative)).
All tumors are checked for hormone receptors. A pathologist determines the receptor status by testing the tumor tissue removed during a biopsy.
Most breast cancers are hormone receptor-positive.
Hormone therapies are only used to treat hormone receptor-positive breast cancers.
Learn more about hormone receptor status.
How do they work?
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.
They do this in a few ways.
- Some hormone therapies, like the drug tamoxifen, attach to the receptor in the cancer cell and block estrogen from attaching to the receptor.
- Other therapies, like aromatase inhibitors, lower the level of estrogen in the body so the cancer cells cannot get the estrogen they need to grow.
Treatment with the hormone therapies tamoxifen and/or aromatase inhibitors lowers the risk of [70-71]:
- Breast cancer recurrence
- Breast cancer in the opposite breast
- Death from breast cancer
Learn more about tamoxifen.
Learn more about aromatase inhibitors.
Hormone therapy versus menopausal hormone therapy
Hormone therapy for breast cancer treatment is different than menopausal hormone therapy (MHT). MHT may also be called postmenopausal hormone use or hormone replacement therapy.
Hormone therapies used in breast cancer treatment block hormone actions or lower hormone levels in the body. Although these drugs are called hormone therapies, they act as “anti-hormone” therapies.
By contrast, MHT is meant to increase hormone levels in the body to treat menopausal symptoms.
MHT increases the risk of breast cancer and is only recommended at the lowest dose that eases symptoms for the shortest time needed.
Learn more about MHT and breast cancer risk.
Hormone therapy drugs
Figures 5.7 and 5.8 list common hormone therapies for early, locally advanced and metastatic breast cancer.
Figure 5.7: Hormone therapies commonly used to treat early and locally advanced breast cancer |
Drug | Brand name | Used in pre- or postmenopausal women? | Injection or pill? |
Tamoxifen | Nolvadex | Pre- and postmenopausal | Pill |
Anastrozole | Arimidex | Postmenopausal | Pill |
Letrozole | Femara | Postmenopausal | Pill |
Exemestane | Aromasin | Postmenopausal | Pill |
Goserelin | Zoladex | Premenopausal | Injection |
Leuprolide | Lupron | Premenopausal | Injection |
Adapted from Murphy et al. [72].
To learn more about a specific hormone therapy, visit the National Institutes of Health’s Medline Plus website.
Figure 5.8: Hormone therapies commonly used to treat metastatic breast cancer |
Drug | Brand name | Used in pre- or postmenopausal women? | Injection or pill? |
Anastrozole | Arimidex | Postmenopausal | Pill |
Exemestane | Aromasin | Postmenopausal | Pill |
Fulvestrant | Faslodex | Postmenopausal | Injection |
Goserelin | Zoladex | Premenopausal | Injection |
Letrozole | Femara | Postmenopausal | Pill |
Leuprolide | Lupron | Premenopausal | Injection |
Megestrol acetate | Megace | Pre- and postmenopausal | Pill |
Tamoxifen | Nolvadex | Pre- and postmenopausal | Pill |
Toremifene | Fareston | Postmenopausal | Pill |
Tamoxifen can be used to treat hormone-receptor positive breast cancer in premenopausal women, postmenopausal women and men.
Learn more about tamoxifen.
Aromatase inhibitors can be used to treat hormone-receptor positive breast cancer in postmenopausal women.
Aromatase inhibitors may also be used to treat some premenopausal women who are also getting ovarian suppression.
Learn more about aromatase inhibitors.
Learn more about ovarian suppression and aromatase inhibitors.
One way to slow the growth of hormone receptor-positive breast cancer in premenopausal women is ovarian suppression.
Ovarian suppression uses drug therapy or surgery to prevent the ovaries from making estrogen.
Learn more about ovarian suppression.
- Do I need hormone therapy? Why?
- What tests were done on my tumor? What were the estrogen receptor status and progesterone receptor status of my tumor? How do these affect my treatment plan?
- Which hormone therapy do you recommend for me and why? How does this therapy treat my breast cancer?
- How will hormone therapy affect my risk of having a breast cancer recurrence, metastasis or a new breast cancer? Please explain the differences to me.
- Is there a clinical trial you recommend I join?
- What are the short- and long-term side effects of this hormone therapy? What side effects should I report to you?
- Are there medications I should avoid while using hormone therapy?
- Is there a generic form of this hormone therapy?
- How soon after surgery will I begin hormone therapy?
- In what form and how often will the hormone therapy be given?
- How long will I be on hormone therapy? How will that decision be made?
- Will I need extra tests or exams? If so, which tests and how often will they be needed?
- Will I be given a baseline bone density test if I will take an aromatase inhibitor? How will you follow my bone density status? What can be done to help reduce bone loss if it happens while taking an aromatase inhibitor? What signs or symptoms of bone loss should I report to you?
- Should I continue to see my regular physician or gynecologist during my treatment?
- How often will I have check-ups and follow-up tests after treatment ends?
- Will a follow-up care plan be prepared for me?
- Which health care provider is in charge of my follow-up care?
- Where can I find a support group for breast cancer survivors (or cancer survivors in general)?
- What do I need to consider before treatment if I would like to have a child after I have been treated for breast cancer?
Learn more about
talking with your healthcare provider.
Treatment guidelines
Although the exact treatment for breast cancer varies from person to person, guidelines help ensure high quality care. These guidelines are based on the latest research and agreement among experts.
The National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO) are two respected organizations that regularly review and update their guidelines.
In addition, the National Cancer Institute (NCI) has treatment overviews.
Talk with your health care providers about which treatment guidelines they use. Since there’s often a lag time between the latest research and guideline updates, most providers prefer to base their treatment on the latest research.
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.
It’s important to follow the treatment plan (for medications and other therapies) prescribed by your health care provider in terms of:
Completing hormone therapy
Hormone therapy with tamoxifen and/or aromatase inhibitors is prescribed for 5-10 years. The length of treatment coupled with side effects can make it tough to complete hormone therapy.
Dealing with menopausal symptoms related to hormone therapy can be hard. Talk with your health care provider about ways to ease these and other side effects.
To get the most benefit from hormone therapy, you need to take the full course of treatment. People who complete the full course have better survival than those who do not [73-75].
If you have trouble remembering to take your hormone therapy, a pillbox or setting an alarm on your watch or phone (you may be able to download an app) may help [3].
However, you do not need to panic if you miss a day or two.
Learn more about the importance of following your breast cancer treatment plan.
Prescription drug assistance
Hormone therapy drug costs can quickly become a financial burden for you and your family.
Medicare and many insurance providers offer prescription drug plans. One may already be included in your policy or you may be able to buy an extra plan for prescriptions.
Tamoxifen and aromatase inhibitors (anastrozole, exemestane and letrozole) all have generic forms. Generics cost less than name brand drugs, 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.
Susan G. Komen®'s position on fairness in breast cancer medication coverage |
Medications taken by mouth (oral) are usually covered under a health insurance plan’s prescription drug benefit rather than the plan’s medical benefit. As a result, people often find themselves facing high out-of-pocket costs when filling their prescriptions (sometimes costing thousands of dollars a month). High prescription drug costs are a barrier to care. They can prevent people from getting the medications prescribed by their health care provider. Komen supports state and federal efforts to require insurers to provide the same or better coverage for oral breast cancer medications as they do for IV medications. This would help ensure patients have access to affordable, appropriate treatment. |
Clinical trials
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 will become part of standard care.
After discussing the benefits and risks with your health care provider, we encourage you to consider joining a clinical trial.
BreastCancerTrials.org in collaboration with Susan G. Komen® offers a custom matching service to help you find a clinical trial that fits your health needs. Search BreastCancerTrials.org for clinical trials on hormone therapies.
Learn more about clinical trials.
SUSAN G. KOMEN® SUPPORT RESOURCES |
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* 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 at this time.