Eligible participants will be those diagnosed with HER2-positive, unresectable or metastatic breast cancer, who have received one prior HER2-targeted therapy and are now scheduled to receive T-DXd in second line.~Further, all eligible participants are offered to use CANCADO PRO-React Onco, an in Germany approved and reimbursed digital healthcare application (DiGA) for assistance of patients with breast cancer and their oncologist during cancer treatment.~All diagnostic and treatment procedures including visit frequency are at the discretion of the treating physician and not defined by the protocol. T-DXd treatment and DiGA are considered as a selection criteria.~Approximately 390 eligible participants will be enrolled into 1 of 2 cohorts, according to the CANKADO PRO-React Onco user behavior.
This is a prospective non-interventional, multicenter study observing patient reported outcomes as well as real-world efficacy and safety of trastuzumab deruxtecan in patients with Human epidermal growth factor receptor 2 (HER2)-positive unresectable or metastatic breast cancer, who were offered to use CANKADO PRO-React Onco, in Germany.