Patients with estrogen receptor (ER)-positive breast cancer generally do not have significant response to neoadjuvant chemotherapy. In these patients, neoadjuvant endocrine therapy (NET) is an alternative for those who may benefit from tumor downsizing prior to surgery. This article reviews clinical trials that have defined the role of NET. Cumulatively, these trials demonstrate that NET is effective in downsizing ER-positive breast tumors. Aromatase inhibitors are preferred in postmenopausal patients. An aromatase inhibitor with ovarian suppression is effective in premenopausal patients. While trials to date have shown the effectiveness of NET to facilitate breast conservation, they have provided little data regarding optimal axillary management.
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T.A.K. has received speaker fees from Genomic Health. E.A.M. reports receiving honoraria from Physician Education Resource; paid compensation for participation on Scientific Advisory Boards for Genomic Health, Merck, Paregrine Pharmaceuticals, Sella Life Science, and Tapimmune; and research funding from Glaxo SmithKline. Her institution has received research funding from Astra Zeneca, EMD Serono, Galena Biopharma, and Genentech/Roche.
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Weiss, A., King, T.A. & Mittendorf, E.A. The Landmark Series: Neoadjuvant Endocrine Therapy for Breast Cancer. Ann Surg Oncol 27, 3393–3401 (2020). https://doi.org/10.1245/s10434-020-08530-6