To our knowledge, from 2007 to 2019, twenty cost-effectiveness surveys of one-year adjuvant trastuzumab in cases of early HER2-positive breast cancer were published worldwide [9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28]. The gene discussed is ERBB2; the disease is breast cancer.