title: Hormone receptor status predicts the clinical outcome of human epidermal growth factor 2-positive metastatic breast cancer patients receiving trastuzumab therapy: a multicenter retrospective study.
abstract: OBJECTIVE
  Trastuzumab, a humanized monoclonal antibody that binds human epidermal growth factor receptor 2 (HER2), dramatically improves the clinical outcomes of HER2-positive breast cancer. Emerging evidence implied that the clinical behavior and sensitivity to targeted agents in HER2-positive breast cancer differed by hormone receptor (HR) status. The objective of this study was to determine the effect of the HR status on survival benefit of HER2-positive metastatic breast cancer when treated with anti-HER2-targeted therapy in People's Republic of China.
  
  
  METHODS
  Metastatic breast cancer patients with HER2-positive diseases across six cancer centers in People's Republic of China were retrospectively analyzed in our study. Patients were classified into four groups according to HR/HER2 status and trastuzumab treatment: HER2+/HR+ patients with first-line trastuzumab treatment, HER2+/HR+ patients with no trastuzumab treatment, HER2+/HR- patients with first-line trastuzumab treatment, and HER2+/HR- patients with no trastuzumab treatment. Kaplan-Meier analysis, log-rank test, and multivariate analysis were performed during analysis.
  
  
  RESULTS
  A total of 295 patients were included in the final analysis. The median overall survival was 30 months (95% confidence interval: 27.521-32.479). Among patients with HER2+/HR- disease, significant survival benefit was observed when treated with trastuzumab (30 vs 21 months, P=0.000). However, in patients with HER2+/HR+ disease, trastuzumab administration had a survival improvement trend but no significant statistical differences (36 vs 30 months, P=0.258). In the multivariate analysis, HR status was an independent predictor of overall survival and trastuzumab treatment had significantly decreased risk of death in HER2+/HR- patients (hazard ratio =0.330).
  
  
  CONCLUSIONS
  HR status is an independent predictor of overall survival in HER2-positive metastatic breast cancer patients and patients with HER2+/HR- subtype might be associated with more survival benefits when treated with trastuzumab-based regimens.
authors.affiliation: Department of Breast Cancer, Beijing Shijitan Hospital, Capital Medical University, Beijing, People's Republic of China.
authors.forename: Yunchao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Oncology, Liaoning Cancer Hospital and Institute, Shenyang, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Sun
authors.affiliation: Department of Oncology, China-Japan Friendship Hospital, Beijing, People's Republic of China.
authors.forename: Donggui
authors.initials: D
authors.lastname: Wan
authors.affiliation: Department of Oncology, Shandong Cancer Hospital, Jinan, People's Republic of China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Sheng
authors.affiliation: Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Oncology, Jiangsu Cancer Hospital of Nanjing Medical University, Nanjing, People's Republic of China.
authors.forename: Huayun
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Breast Cancer, Beijing Shijitan Hospital, Capital Medical University, Beijing, People's Republic of China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Breast Cancer, Beijing Shijitan Hospital, Capital Medical University, Beijing, People's Republic of China ; Division of Hematology and Oncology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
authors.forename: Janice
authors.initials: J
authors.lastname: Lu
keywords: HER2-positive; hormone receptor status; metastatic breast cancer