Pyrotinib for HER2-Positive Advanced Breast Cancer Previously Treated With Trastuzumab and Pertuzumab

Retrospective Analysis of Pyrotinib in the Treatment of HER2-Positive Advanced Breast Cancer Previously Treated With Trastuzumab and Pertuzumab

In China, pyrotinib is used for patients with HER2-positive advanced breast cancer who have progressed on trastuzumab. As anti-HER2 antibody therapy has advanced from trastuzumab monotherapy to trastuzumab-pertuzumab dual-target treatment, few clinical studies have investigated pyrotinib's efficacy among patients pre-treated with this dual-antibody regimen. This is a retrospective observational cohort study, which aims to assess the efficacy and safety of pyrotinib in this patient cohort.

Inclusion Criteria:

• 1. Diagnosis of unresectable locally advanced or metastatic breast cancer 2. Confirmed HER2-positive status, defined as immunohistochemistry (IHC) 3+ or IHC 2+ with positive in situ hybridization (ISH) results 3. Prior systemic treatment of trastuzumab and pertuzumab 4. Adequate baseline cardiac, bone marrow, renal, hepatic, and blood coagulation functions 5. Life expectancy > 3 months 6. ECOG ≤3

Exclusion Criteria:

• 1. Incomplete clinical case data