Efficacy and Safety of T-DXd in Patients With HER2-positive and HER2-low Metastatic Breast Cancer: a Real-world Study

Efficacy and Safety of T-DXd in Patients With HER2-positive and HER2-low Metastatic Breast Cancer: a Real-world Study

Evaluate the efficacy and safety of T-DXd in patients with HER2-positive and HER2-low metastatic breast cancer

The DESTINY-Breast trials established trastuzumab deruxtecan (T-DXd) as a treatment significantly improving outcomes in human epidermal growth factor receptor 2 (HER2)-positive and HER2-low metastatic breast cancer (MBC). However, real-world effectiveness is susceptible to confounding factors. This multicenter, real-world study aims to systematically evaluate the efficacy and safety of T-DXd in patients with HER2-positive and HER2-low MBC. Key clinicopathological parameters were to be integrated to develop an individualized prognostic prediction model, facilitating precision medicine implementation in clinical practice.

Inclusion Criteria:

1. female patients aged ≥18 years;
2. histologically confirmed HER2-positive (IHC 3+ or IHC 2+/FISH+) or HER2-low (IHC 1+ or IHC 2+/FISH-) disease;
3. radiologically confirmed recurrent or metastatic disease;
4. completion of ≥2 cycles of T-DXd therapy;
5. comprehensive medical documentation;
6. Eastern Cooperative Oncology Group (ECOG) performance status ≤3;
7. measurable target lesions according to RECIST 1.1

Exclusion Criteria:

1. history of interstitial lung disease
2. incomplete medical records
3. concurrent malignancies;
4. pregnancy or lactation
5. psychiatric disorders compromising treatment adherence