Clinical and molecular characteristics of HER2-low-positive breast cancer: pooled analysis of individual patient data from four prospective, neoadjuvant clinical trials

This pooled analysis of 2310 patients from four neoadjuvant clinical trials examined survival and treatment response in patients with HER2-low-positive (immunohistochemistry 1+ or 2+/in-situ hybridisation negative; n=1098) versus HER2-zero (immunohistochemistry0; n=1212) breast cancer. HER2-low-positive tumours had significantly lower pathological complete response (29.2% vs. 39%; p=0.0002). This was also seen in the hormone receptor positive subgroup (17.5% vs. 23.6%; p=0.024), but not in the hormone receptor negative subgroup (50.1% vs. 48%; p=0.21). Patients with HER2-low-positive tumours had significantly longer survival (3 year DFS 83.4% vs. 76.1%; p=0.0084). This was seen in hormone receptor negative tumours (3 year DFS 84.5% vs. 74.4%; p=0.0076), but not in hormone receptor positive tumours (3 year DFS 82.8% vs. 79.3%; p=0.39).  

Classifications: Breast Cancer Treatment

Keywords: HER2 Positive