Influencing Factors of Prognosis in Adjuvant Trastuzumab Therapy for HER2-Positive Breast Cancer

ObjectiveThis study aims to conduct a comprehensive, multidimensional evaluation of how clinical and pathological factors influence invasive disease-free survival (IDFS) and cancer-specific survival (CSS) in patients with human epidermal growth factor receptor 2 (ERBB2/HER2) positive breast cancer receiving adjuvant trastuzumab therapy. Additionally, a stratified assessment will be conducted based on the hormone receptor (HR) status; thereby providing a practical basis for clinical treatment.MethodA total of 643 patients with HER2-positive breast cancer who received adjuvant trastuzumab therapy were retrospectively included. The patients' clinical and pathological information, as well as IDFS and CSS data, were systematically collected and evaluated. Survival analysis was conducted via the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards regression models were used to assess the effects of menstrual status, tumor size, vascular invasion, lymph node involvement, histological grade, histological type, HR status, MKI67 expression, tumor-infiltrating lymphocytes (TILs), HER2 expression, and anthracycline-based chemotherapy on IDFS and CSS. Additionally, clinicopathological characteristics of patients with HER2-positive breast cancer who received trastuzumab treatment were analyzed.ResultAmong all patients, HER2(3+), absence of lymph node metastasis, and anthracycline-based chemotherapy were independently associated with prolonged CSS. Notably, anthracycline use was an independent predictor of longer CSS in HR-negative patients. In the HR-positive subgroup, patients with HER2(3+) status demonstrated a significant CSS benefit compared to those with HER2(2+)/FISH(+) status.ConclusionHER2 expression status affects CSS in patients with HER2-positive breast cancer receiving adjuvant trastuzumab therapy. HR-negative patients may derive clinical benefit from anthracyclines, providing evidence to support anthracycline-based regimens combined with trastuzumab as the adjuvant treatment for HR-negative, HER2-positive breast cancer.