The introduction of human epidermal growth factor receptor 2 (HER2)–targeted drugs into routine clinical practice has a dramatic effect on the outlook for patients with HER2-positive breast cancer (BC). However, the association between efficacy of HER2-targeted therapy and hormone receptor (HR) status is still unclear. Here we conducted a meta-analysis of randomized controlled trials (RCTs) to address this issue in both neoadjuvant and adjuvant settings. PubMed and EMBASE were searched from

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... ption to October 2017 for studies involving trastuzumab, lapatinib, pertuzumab, trastuzumab emtansine and neratinib. Efficacy endpoints were pathological complete response (pCR) for neoadjuvant therapy and disease-free survival (DFS) for adjuvant therapy. In neoadjuvant setting, pCR was reported in 7 trials with 2868 subjects. Hormone receptor (HR)–negative women derived substantially greater benefit from HER2-targeted agents than did HR-positive patients (odds ratio (OR), 2.34; 95% confidence interval (CI), 1.99–2.75). Additionally, the impact of HR status on pCR was independent of anti-HER2 agents. In adjuvant setting, DFS was investigated in 7 studies with 12,768 patients. HR-positive patients benefit more from anti-HER2 treatment than did HR-negative subjects (OR, 0.81; 95% CI, 0.74–0.89). Moreover, patients who did not receive any endocrine or anti-HER2 neoadjuvant treatment showed similar outcome but with a smaller effect (OR, 0.88; 95% CI, 0.78–0.99). In summary, compared with HER2-positive/HR-negative subjects, HER2-positive/HR-positive patients achieved greater benefit from HER2-targeted treatment although the efficacy from neoadjuvant therapy was relatively poor.