Hormone therapy (also called hormonal therapy, hormone treatment, or endocrine therapy) slows or stops the growth of hormone-sensitive tumors by blocking the body’s ability to produce hormones or by interfering with effects of hormones on breast cancer cells. Six in seven women at risk of breast cancer are opting out of taking a preventative drug called tamoxifen, a new study has found. Researchers said there were three main factors for why they. Tamoxifen (Nolvadex), a hormone therapy drug, is used to treat breast cancers and to lower risk in women at high risk of breast cancer. Read about Tamoxifen side-effects here. Tamoxifen is used for the treatment of invasive breast cancer in men and women, the most common type of breast cancer, following surgery and/or radiation and for preventing invasive breast cancer in women at high risk for developing it. Tamoxifen is the oldest of the hormonal therapies, drugs that block the effects of estrogen in the breast tissue. Tamoxifen is approved by the FDA to treat people diagnosed with both early-stage and advanced-stage hormone-receptor-positive breast cancer. Learn more about tamoxifen in pill form. Tamoxifen blocks the actions of estrogen and is used to treat and prevent some types of breast cancer. Learn about side effects, interactions and indications. Tamoxifen (Nolvadex) is a medication used to treat hormone-receptor positive early and metastatic breast cancers and to reduce breast cancer risk in undiagnosed women at higher-than-average risk of developing breast cancer. Learn more about tamoxifen. Tamoxifen and raloxifene have been shown to reduce the risk breast cancer, but they can have their own risks and side effects. Tamoxifen and raloxifene are the only drugs that are approved in the US to help lower the risk of breast cancer, although for some women, drugs called aromatase inhibitors might be an option as well. Davies C, Pan H, Godwin J, et al. Long-term effects of continuing adjuvant tamoxifen to 10 years versus stopping at 5 years after diagnosis of oestrogen receptor-positive breast cancer: ATLAS, a randomised trial.Lancet The drug tamoxifen is approved by the U.S. Food and Drug Administration (FDA) to help treat early and advanced stages of breast cancer and prevent breast cancer recurrence (return).