Fig. 1

Patient disposition. A Aged ≥ 20 years at the start of drug therapy following T-DM1 treatment discontinuation. B Not pathologically diagnosed with unresectable and/or metastatic human epidermal growth factor receptor 2 (HER2)-positive breast cancer. C Did not start at least one line of drug therapy (anti-HER2 therapy, molecular targeted therapy, chemotherapy, and endocrine therapy) for unresectable and/or metastatic HER2-positive breast cancer following T-DM1 treatment discontinuation between 1 January 2014 and 31 December 2018. D At least one line of drug therapy (anti-HER2 therapy, molecular targeted therapy, chemotherapy, and endocrine therapy) was started for unresectable and/or metastatic HER2-positive breast cancer following T-DM1 treatment discontinuation, but the start date was 1 January 2019 or later. T-DM1 trastuzumab emtansine