When are hormone therapies used?
Some breast cancer cells need estrogen and/or progesterone (female hormones that are produced in the body) to grow. When these hormones attach to special proteins called hormone receptors, the cancer cells with these receptors grow. Tumor cells that have these receptors are “hormone receptor-positive” (estrogen receptor-positive and/or progesterone receptor-positive). All tumors are checked for these markers. A pathologist determines the receptor status by testing the tumor tissue that is removed during a biopsy.
Hormone therapies are only used to treat hormone receptor-positive breast cancers.
Learn more about hormone receptor status.
How do hormone therapies 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 can 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 that 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 [45-46]:
- Breast cancer recurrence
- Breast cancer in the opposite breast
- Death from breast cancer
Hormone therapy versus hormone replacement therapy (postmenopausal hormone use)
Hormone therapy for breast cancer is different from hormone replacement therapy (postmenopausal hormone use). Hormone therapies are drugs that block hormone actions or lower hormone levels in the body. In contrast, hormone replacement therapies are meant to replace natural hormones in the body to ease menopausal symptoms.
Hormone therapy drugs
Figures 5.7 and 5.8 list the common hormone therapies for early, locally advanced and metastatic breast cancer. These figures do not include rarely used drugs or those no longer in use.
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 Table 1. Murphy et al. 1997 [47].
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
|
Fulvesterant
|
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
|
To learn more about a specific hormone therapy, visit the National Institutes of Health’s Medline Plus website.
Hormone therapy guidelines
Although the exact treatment for breast cancer varies from person to person, some organizations have guidelines to help ensure quality care. These guidelines are based on the latest research and the consensus of experts. The American Society of Clinical Oncology (ASCO) and National Comprehensive Care Network (NCCN) are two respected organizations that regularly update and post their guidelines online. The National Cancer Institute (NCI) also has overviews of treatment options.
Importance of following your breast cancer treatment plan
The importance of adherence (compliance)
Breast cancer treatment is most effective when all parts of the treatment plan are followed. Adherence (also called compliance) is how closely people follow the treatment plan (for medicines and other therapies) prescribed by their health care providers in terms of:
Completing hormone therapy
Hormone therapy with tamoxifen and/or aromatase inhibitors is typically prescribed for at least five years. The length of treatment coupled with side effects can make adherence to hormone therapy difficult. Although the menopausal symptoms related to hormone therapy can be hard to deal with, there are treatments that may ease these side effects. If you have side effects with hormone therapy, talk to your health care provider about ways to treat them.
To get the most benefit of hormone therapy, you need to take the full course of treatment. Women who complete the full treatment course have higher rates of survival [48-49].
If you have trouble remembering to take your hormone therapy, a daily pillbox or setting an alarm on your watch or phone may be helpful [2]. However, you do not need to panic if you miss a day or two.
Learn more about adherence.
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 some aromatase inhibitors are off-patent and available in a generic form. Generics are cheaper than name brand drugs, but are just as effective.
You may also qualify for assistance from programs that help with drug costs or offer low-cost or free prescriptions. Learn more about insurance plans and prescription drug assistance programs.
Updated 05/21/11
