The Prognostic Impact of HER2 Expression in Non-Metastatic HER2-Positive Breast Cancer Treated With Dual HER2-Targeted Therapy

Shandong Cancer Hospital and Institute300 enrolled

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.

Study Type

OBSERVATIONAL

Enrollment

300

Conditions

Breast Cancer HER2/CEP17 Ratio

Eligibility

Sex: FEMALEMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Age ≥18 years. 2. Pathologically confirmed primary breast cancer, clinical stage I-III (AJCC 8th Edition). 3. HER2-positive status confirmed by FISH testing (per ASCO/CAP guidelines) with available HER2/CEP17 ratio. 4. Received at least one dose of dual-target therapy (trastuzumab combined with pertuzumab) in the adjuvant or neoadjuvant setting. 5. Underwent curative-intent surgery (mastectomy or breast-conserving surgery). Exclusion Criteria: 1. Presence of distant metastasis (Stage IV) or contralateral breast cancer at initial diagnosis. 2. Previous anti-HER2 targeted therapy prior to dual-target treatment. 3. Missing key clinical data (e.g., HER2 FISH results, treatment regimen, surgery date). 4. Carcinoma in situ or occult breast cancer, non-primary breast cancer, or concurrent other malignancies. 5. Loss to follow-up or follow-up duration \<3 months (unless recurrence or death occurred within this period).

Outcomes

Primary Outcomes

Disease-free survival based on HER2/CEP17 ratio

Defined as the period from the date of pathological diagnosis until the date of the first relapse, appearance of non-breast primary cancer, death with no signs or symptoms of recurrence or metast, or the last recorded follow-up ,whichever came first.

Time frame: From the date of pathological diagnosis to event with follow-up duration ≥3 months (unless recurrence or death occurred within 3 month).