Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Aug 6, 2019; 7(15): 1937-1953
Published online Aug 6, 2019. doi: 10.12998/wjcc.v7.i15.1937
Neoadjuvant endocrine therapy: A potential strategy for ER-positive breast cancer
Li-Tong Yao, Mo-Zhi Wang, Meng-Shen Wang, Xue-Ting Yu, Jing-Yi Guo, Tie Sun, Xin-Yan Li, Ying-Ying Xu
Li-Tong Yao, Mo-Zhi Wang, Meng-Shen Wang, Xue-Ting Yu, Jing-Yi Guo, Tie Sun, Xin-Yan Li, Ying-Ying Xu, Department of Breast Surgery, the First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China
Author contributions: Yao LT and Wang MZ contributed equally to the writing and critical revision of this manuscript; Wang MS, Yu XT, and Guo JY collected and analyzed the relevant literature; Sun T and Li XY contributed to paper revision and editing; Xu YY is the corresponding author and responsible for the conception, funding, and finalization.
Supported by the National Natural Science Foundation of China, No. 81773083.
Conflict-of-interest statement: The authors have no conflict of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Ying-Ying Xu, PhD, Professor, Department of Breast Surgery, the First Affiliated Hospital of China Medical University, No. 155, North Nanjing Street, Shenyang 110001, Liaoning Province, China.
Telephone: +86-24-83282741 Fax: +86-24-22703578
Received: April 8, 2019
Peer-review started: April 8, 2019
First decision: May 31, 2019
Revised: June 21, 2019
Accepted: July 3, 2019
Article in press: July 3, 2019
Published online: August 6, 2019

A potential strategy for patients with estrogen receptor (ER)-positive breast cancer is necessary to replace neoadjuvant chemotherapy which has limited benefit. Neoadjuvant endocrine therapy (NAE) has been indicated to be a favorable alternate approach to downstage large or locally advanced breast cancer in ER-positive, human epidermal growth factor receptor 2 (HER2)-negative (ER+/HER2-) patients, especially postmenopausal women. Previous studies have demonstrated the efficacy of various endocrine agents in NAE. Aromatase inhibitors (AIs) have proven superiority over tamoxifen as a suitable choice to optimize treatment efficacy. Fulvestrant was recently reported as an effective agent, similar to AIs. Furthermore, the addition of targeted agents exerts synergistic antiproliferative effects with endocrine agents and rapidly improves response rates in both endocrine sensitive and resistant tumors. The neoadjuvant platform provides a unique opportunity to define the appropriate strategy and address the mechanisms of endocrine resistance. In addition, the predictive value of biomarkers and genomic assays in NAE is under investigation to evaluate individual effects and validate biomarker-based strategies. In this review, we discuss the most relevant evidence on the potential of NAE for ER+ breast cancer. The current understanding also offers new insights into the identification of the optimal settings and valuable predictive tools of NAE to guide clinical treatment decisions and achieve beneficial therapeutic effects.

Keywords: Breast cancer, Neoadjuvant endocrine therapy, Neoadjuvant chemotherapy, Aromatase inhibitor, Palbociclib, Ki67, Genomic assay

Core tips: Neoadjuvant endocrine therapy (NAE), either alone or combined with other therapies, is a valuable alternate approach to ER-positive breast cancer. Our objective is to define the optimal settings for suitable individuals, including optimal treatment duration, endocrine agents, and targeted agents in NAE. The identification of correct patients for NAE remains unknown and requires further validation corresponding to biomarker-based strategies. This review consolidates the current relevant evidence to verify the potential value and discuss the development prospects of NAE.