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

Yunchao Wang,1 Tao Sun,2 Donggui Wan,3 Lijun Sheng,4 Wei Li,5 Huayun Zhu,6 Yanping Li,1 Janice Lu1,7 1Department of Breast Cancer, Beijing Shijitan Hospital, Capital Medical University, Beijing, 2Department of Oncology, Liaoning Cancer Hospital and Institute, Shenyang, 3Department of Oncology, China-Japan Friendship Hospital, Beijing, 4Department of Oncology, Shandong Cancer Hospital, Jinan, 5Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, 6Department of Oncology, Jiangsu Cancer Hospital of Nanjing Medical University, Nanjing, People’s Republic of China; 7Division of Hematology and Oncology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA Objectives: 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).Conclusion: 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. Keywords: HER2-positive, metastatic breast cancer, hormone receptor status