Breast Cancer Home > What Is Tamoxifen Used For?
How Does Tamoxifen Work?Tamoxifen is part of a group of medications called selective estrogen receptor modulators (SERMs). SERMs have both estrogenic (estrogen-like) effects and anti-estrogenic effects. Tamoxifen has anti-estrogenic effects on the breasts, while it has estrogen-like effects on bones, helping to strengthen them.
Many breast cancers are sensitive to the estrogen hormone, meaning that the tumor grows with the help of it. When a tumor is sensitive to estrogen, it has receptors on the outer surface of its cells, which estrogen fits into like a key opening a lock. When this connection is made, the cancer grows. Breast cancers that have estrogen (and/or progesterone) receptors are known as hormone receptor-positive tumors.
Tamoxifen binds to estrogen receptors in the breast, preventing the hormone from binding. By decreasing these effects of estrogen, the drug can help decrease the growth of these breast cancers. This type of breast cancer treatment is known as hormonal therapy.