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Therapies that block estrogen’s effects
Source: Hormone Therapy for Breast Cancer, National Cancer Institute.
Source updated: December 2, 2025 · Captured 2026-09-09.
Selected source text with whitespace normalised. This Triangle page is not an NCI PDQ summary. Independent clinical review is pending.
NCI patient treatment article for this disease Exact source article; not a clinically reviewed indication or current-standard recommendation.
Context: Hormone Therapy for Breast Cancer / What types of hormone therapy are used for breast cancer?
Two types of drugs interfere with estrogen’s ability to stimulate the growth of breast cancer cells:
Selective estrogen receptor modulators (SERMs) bind to estrogen receptors. In breast cells, SERMs block the effects of estrogen, but in some other cells, such as bone, SERMs act like estrogen. SERMs used to treat breast cancer include:
Selective estrogen receptor modulators (SERMs) bind to estrogen receptors. In breast cells, SERMs block the effects of estrogen, but in some other cells, such as bone, SERMs act like estrogen. SERMs used to treat breast cancer include:
tamoxifen, which is used in both premenopausal and postmenopausal women
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Selective estrogen receptor modulators (SERMs) bind to estrogen receptors. In breast cells, SERMs block the effects of estrogen, but in some other cells, such as bone, SERMs act like estrogen. SERMs used to treat breast cancer include:
toremifene, which is used only in postmenopausal women
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Selective estrogen receptor degraders (SERDs), sometimes called pure antiestrogens, bind strongly to estrogen receptors. In addition to blocking the effects of estrogen, they destroy estrogen receptors. Fulvestrant is a SERD approved to treat breast cancer. It is used only in postmenopausal women.
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Preserved source evidence · Independent clinical review pending · Not medical advice