Hormonal therapy medicines such as tamoxifen, the aromatase inhibitors (Arimidex [chemical name: anastrozole], Aromasin [chemical name: exemestane], and Femara [chemical name: letrozole]), and Faslodex (chemical name: fulvestrant) are used to help shrink or slow the growth of hormone-receptor-positive metastatic breast cancer. Hormonal therapy will not work on hormone-receptor-negative breast cancer.
Hormonal therapy medicines treat hormone-receptor-positive breast cancers in two ways:
- by lowering the amount of the hormone estrogen in the body
- by blocking the action of estrogen in the body
Because it targets estrogen, hormonal therapy is also known as anti-estrogen therapy.
The American Society of Clinical Oncologists (ASCO) recommends hormonal therapy based on cancer stage and menopausal status. ASCO recommends that pre- or postmenopausal women diagnosed with advanced (metastatic) hormone-receptor-positive breast cancer consider taking an aromatase inhibitor after 2 to 5 years of tamoxifen, or whenever the cancer stops responding to tamoxifen. If the cancer stops responding to an aromatase inhibitor and tamoxifen, consider Faslodex.
Women taking hormonal therapy to treat metastatic hormone-receptor-positive breast cancer usually take hormonal therapy for as long as it works. If the cancer stops responding to one hormonal therapy medicine, your doctor usually will recommend a different hormonal therapy medicine.
After any period of time from a few months or several years, the cancer may progress while you're taking hormonal therapy. Your doctor then may recommend chemotherapy. You may stop taking hormonal therapy when you start chemotherapy or you may continue hormonal therapy. Your doctor also may recommend targeted therapies if they're appropriate for your type of cancer.
To learn more about hormonal therapy, including possible side effects and how it's taken, visit the Breastcancer.org Hormonal Therapy section.