The study aims to evaluate real-world efficacy and toxicity data of treatment with Trastuzumab deruxtecan (T-DXd), a HER2-targeting ADC and sacituzumab govitecan (SG), a TROP-2-targeting ADC in pretreated patients with advanced breast cancer.

Antibody-drug conjugates (ADCs) have significantly changed the therapeutic landscape of advanced breast cancer. Trastuzumab deruxtecan (T-DXd), a HER2-targeting ADC and sacituzumab govitecan (SG), a TROP-2-targeting ADC, recently demonstrated superior efficacy over standard of care treatments depending on breast cancer subtype. The study aims to evaluate real-world efficacy and toxicity data of treatment with T-DXd and SG in pretreated patients with advanced breast cancer.

This study includes a retrospective/prospective multicenter review of medical records of patients with advanced breast cancer who received treatment with T-DXd and SG at Departments of Oncology, affiliated with the Hellenic Cooperative Oncology Group (HeCOG).

Inclusion Criteria:

• Histologically confirmed metastatic/recurrent breast cancer
• 18 years of age
• Triple-negative (TNBC), HER2-positive and/or hormone receptor positive advanced breast cancer
• Treatment with an ADC at any of line of treatment
• Treatment with at least one cycle of T-DXd and/or SG

Exclusion Criteria:

• NA

This study includes patients with histologically confirmed metastatic/recurrent breast cancer. Patients need to have received treatment with T-DXd and/or SG at Departments of Oncology in Departments of Oncology associated with the Hellenic Cooperative Oncology Group (HeCOG). Eligible patients are 18 years or older, diagnosed with triple-negative (TNBC), HER2-positive and/or hormone receptor positive advanced breast cancer, who received an ADC at any of line of treatment. Patients who received at least one cycle of T-DXd and/or SG are included. Immunohistochemical markers may be determined locally. Treatment with T-DXd and SG is administered per national guidelines.