ERBB2 and neoplasm: In our study, we compared therapeutic response of Varlitinib + Capecitabine (VC) versus Lapatinib + Capecitabine (LC) in patients with human epidermal growth factor receptor 2 (HER2)‐positive metastatic breast cancer (MBC) after trastuzumab therapy, using changes in tumor diameter and volume per tumor location.