ta·​mox·​i·​fen | \tə-ˈmäk-sə-ˌfen \

Definition of tamoxifen 

: an estrogen antagonist C26H29NO used in the form of its citrate especially to treat postmenopausal breast cancer

Examples of tamoxifen in a Sentence

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Phyllis Laccetti, a participant in the study, took the hormonal therapy tamoxifen alone for five years after having a mastectomy in 2007 to treat her breast cancer, even though her doctor’s initial recommendation was to also receive chemotherapy. Peter Loftus, WSJ, "Doctors Suggest Less Chemo, Surgery for Some Cancer Treatments," 3 June 2018 Generally, after surgery, such patients receive endocrine therapy, such as tamoxifen, which is designed to block the cancer-spurring effects of hormones. Laurie Mcginley, Washington Post, "Most women with a common type of early-stage breast cancer can skip chemo, a new report finds," 3 June 2018 Generally, after surgery, such patients receive endocrine therapy, such as tamoxifen, which is designed to block the cancer-spurring effects of hormones. Laurie Mcginley, BostonGlobe.com, "Study finds some with early-stage breast cancer can skip chemotherapy," 3 June 2018 And a Tufts University study, published earlier this year, showed that soy consumption isn’t problematic for women who currently have breast cancer and doesn’t make cancer treatment drugs like tamoxifen less effective. Marygrace Taylor, Good Housekeeping, "Is Soy Good Or Bad For You? We Have The Science-Backed Answer.," 17 May 2017 Part of the treatment is five years of tamoxifen, which can cause birth defects. Julie Ma, The Cut, "25 Famous Women on Struggling With Fertility," 26 Oct. 2017 The remaining seven mutations predispose women to developing a type of breast cancer known as estrogen-receptor-negative breast cancer, which doesn't respond to hormonal therapies, such as the drug tamoxifen. Susan Scutti, CNN, "Breast cancer genetics revealed: 72 new mutations discovered in global study," 23 Oct. 2017 After the genetic testing found the PALB2 mutation, Bradbury suggested Brown also take tamoxifen, an estrogen-modulating medication used both to treat and reduce the risk of breast cancer. Ilene Raymond Rush, Philly.com, "Why the breast cancer gene you may never have heard of could matter," 10 Sep. 2017 Both groups will be offered tamoxifen or other drugs to reduce the risk of recurrence. Laurie Mcginley, chicagotribune.com, "New breast cancer study will assess controversial 'watchful waiting' approach," 2 May 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'tamoxifen.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of tamoxifen

1972, in the meaning defined above

History and Etymology for tamoxifen

probably by recombination & alteration of trans-, oxy, and clomiphene

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The first known use of tamoxifen was in 1972

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ta·​mox·​i·​fen | \ta-ˈmäk-si-ˌfen \

Medical Definition of tamoxifen 

: a selective estrogen receptor modulator that acts as an estrogen antagonist in breast tissue and is administered orally in the form of its citrate C26H29NO·C6H8O7 especially to treat breast cancer or reduce the risk of its development or reoccurrence — see nolvadex

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