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Open Access Highly Accessed Study protocol

Phase II randomized trial of neoadjuvant metformin plus letrozole versus placebo plus letrozole for estrogen receptor positive postmenopausal breast cancer (METEOR)

Jisun Kim1, Woosung Lim2, Eun-Kyu Kim3, Min-Kyoon Kim4, Nam-Sun Paik2, Sang-Seol Jeong5, Jung-han Yoon6, Chan Heun Park7, Sei Hyun Ahn1, Lee Su Kim8, Sehwan Han9, Seok Jin Nam10, Han-Sung Kang11, Seung Il Kim12, Young Bum Yoo13, Joon Jeong14, Tae Hyun Kim15, Taewoo Kang16, Sung-Won Kim17, Yongsik Jung18, Jeong Eon Lee10, Ku Sang Kim18, Jong-Han Yu1, Byung Joo Chae5, So-Youn Jung11, Eunyoung Kang17, Su Yun Choi19, Hyeong-Gon Moon204, Dong-Young Noh204 and Wonshik Han204*

Author Affiliations

1 Department of Surgery, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea

2 Department of Surgery, Ewha Womans University School of Medicine, Seoul, Korea

3 Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological & Medical Sciences, Seoul, Korea

4 Department of Surgery, Seoul National University Hospital, 101 Daehakro, Jongno-gu, Seoul 110-744, Korea

5 Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea

6 Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Hwasun, Korea

7 Department of Surgery, Breast and Thyroid Cancer Center, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea

8 Division of Breast and Endocrine Surgery, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea

9 Department of Surgery, Inje University Sanggye Paik Hospital, Seoul, Korea

10 Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea

11 Center for Breast Cancer, National Cancer Center, Goyang, Republic of Korea

12 Department of Surgery, Yonsei University College of Medicine, Seoul, Korea

13 Department of Surgery, College of Medicine, Konkuk University, Seoul, Korea

14 Breast Cancer Center, Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea

15 Department of Surgery, Inje University, Busan Paik Hospital, Busan, Korea

16 Busan Cancer Center, Department of Surgery, College of Medicine, Pusan National University, Busan, Korea

17 Department of Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea

18 Department of Surgery, Ajou University School of Medicine, Suwon, Korea

19 Division of Breast and Endocrine Surgery, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea

20 Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea

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BMC Cancer 2014, 14:170  doi:10.1186/1471-2407-14-170

Published: 10 March 2014

Abstract

Background

Neoadjuvant endocrine therapy with an aromatase inhibitor has shown efficacy comparable to that of neoadjuvant chemotherapy in patients with postmenopausal breast cancer. Preclinical and clinical studies have shown that the antidiabetic drug metformin has anti-tumor activity. This prospective, multicenter, phase II randomized, placebo controlled trial was designed to evaluate the direct anti-tumor effect of metformin in non-diabetic postmenopausal women with estrogen-receptor (ER) positive breast cancer.

Methods/Design

Patients meeting the inclusion criteria and providing written informed consent will be randomized to 24 weeks of neoadjuvant treatment with letrozole (2.5 mg/day) and either metformin (2000 mg/day) or placebo. Target accrual number is 104 patients per arm. The primary endpoint will be clinical response rate, as measured by calipers. Secondary endpoints include pathologic complete response rate, breast conserving rate, change in Ki67 expression, breast density change, and toxicity profile. Molecular assays will be performed using samples obtained before treatment, at week 4, and postoperatively.

Discussion

This study will provide direct evidence of the anti-tumor effect of metformin in non-diabetic, postmenopausal patients with ER-positive breast cancer.

Trial registration

ClinicalTrials.gov Identifier NCT01589367

Keywords:
Metformin; Letrozole; Neoadjuvant; Estrogen receptor-positive Breast cancer