This is a retrospective, non-interventional, non-comparative, observational cohort study / registry in the Spain. The study design will reflect real-life clinical management of patients with HER2-positive MBC. Type and frequency of actual patient visits and all evaluations will be done as for routine clinical practice.
The analysis of the efficacy and safety results obtained in patients receiving pertuzumab or TDM1 in those early access systems is of utmost importance. These real-world patients with advanced breast cancer may have different characteristics than those enrolled in clinical trials and clinicians must often extrapolate into therapeutic decisions not fully supported by a robust evidence.
