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.
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.
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 [61-63]:
Learn more about tamoxifen.
Learn more about aromatase inhibitors.
Hormone therapy for breast cancer treatment is different from 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 (learn more) and is only recommended at the lowest dose that eases symptoms for the shortest time needed.
Figures 5.7 and 5.8 list the 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
Used in pre- or postmenopausal women?
Injection or pill?
Pre- and postmenopausal
Adapted from Murphy et al. .
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
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.
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.
Research is ongoing to improve hormone therapy.
Learn more about emerging areas in hormone therapy for early and locally advanced breast cancer.
Learn more about emerging areas in hormone therapy for metastatic breast cancer.
Learn more about clinical trials.
Learn more about talking with your healthcare provider.
Although the exact treatment for breast cancer varies from person to person, treatment guidelines help ensure quality care. These guidelines are based on the latest research and the consensus of experts.
The National Comprehensive Cancer Network (NCCN) and American Society of Clinical Oncology (ASCO) are two respected organizations that regularly update and post their guidelines online. The National Cancer Institute (NCI) also has overviews of treatment options.
Breast cancer treatment is most effective when all parts of the treatment plan are followed.
It is important to follow the treatment plan (for medications and other therapies) prescribed by your health care provider in terms of:
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.
Although the menopausal symptoms related to hormone therapy can be hard to deal with, there are things you can do that may ease these and other side effects. Talk with your health care provider about ways to treat them.
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 [64,150].
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 . 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.
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) are all available in 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 per month). High prescription drug costs are a barrier to care. High costs can prevent people from getting the medications prescribed by their health care provider.
Komen supports efforts at the state and federal levels that require insurers to provide coverage for oral breast cancer medications at a rate no less favorable than what they provide for IV medications to ensure patients have access to affordable, appropriate treatment for their cancer.
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 that can help you find a clinical trial that fits your health needs. Search BreastCancerTrials.org for clinical trials on hormone therapies.
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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.
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