Overview
Previous studies suggest that among patients receiving trastuzumab monotherapy, a HER2/CEP17 ratio \>7.0 (ultra-high expression) is associated with poorer disease-free survival (DFS). Dual-target therapy (trastuzumab + pertuzumab) has become the standard treatment for high-risk HER2-positive breast cancer; however, whether it can predict outcomes in patients with ultra-high HER2 expression remains unsupported by clinical data. To analyze the clinicopathological characteristics and prognostic relationship between the HER2 ultra-high expression group and the normal expression group in non-metastatic HER2-positive breast cancer patients who received dual-target therapy.
Eligibility
Inclusion Criteria:
- Age ≥18 years.
- Pathologically confirmed primary breast cancer, clinical stage I-III (AJCC 8th Edition).
- HER2-positive status confirmed by FISH testing (per ASCO/CAP guidelines) with available HER2/CEP17 ratio.
- Received at least one dose of dual-target therapy (trastuzumab combined with pertuzumab) in the adjuvant or neoadjuvant setting.
- Underwent curative-intent surgery (mastectomy or breast-conserving surgery).
Exclusion Criteria:
- Presence of distant metastasis (Stage IV) or contralateral breast cancer at initial diagnosis.
- Previous anti-HER2 targeted therapy prior to dual-target treatment.
- Missing key clinical data (e.g., HER2 FISH results, treatment regimen, surgery date).
- Carcinoma in situ or occult breast cancer, non-primary breast cancer, or concurrent other malignancies.
- Loss to follow-up or follow-up duration \<3 months (unless recurrence or death occurred within this period).