Trastuzumab deruxtecan (T-DXd) as monotherapy is indicated for the treatment of adult patients with unresectable or metastatic HER2-low breast cancer who have received prior chemotherapy in the metastatic setting or developed disease recurrence during or within 6 months of completing adjuvant chemotherapy.
Based on the extended therapeutic indication of Trastuzumab deruxtecan (Enhertu®), a new patient population will be enrolled, comprising adult patients with unresectable or metastatic HR-positive, HER2-low, or HER2-(ultra)low breast cancer who have received at least one endocrine therapy in the metastatic setting and are not considered suitable for endocrine therapy as the next line of treatment.
Adult patient (age ≥ 18 years) with histological or cytological confirmed diagnosis of unresectable and/or mBC
Decision to newly initiate therapy of T-DXd or conventional chemotherapy according to the physicians choice per SmPC
Written and signed Informed Consent to participate in the study
Documented HER2-low status (IHC1+, IHC2+/ISH-)
Pregnancy or breastfeeding
Patients who at time of data collection for this study are participating in or have participated in an interventional study that remains blinded.