Efficacy, toxicity and prognostic factors of pyrotinib‑involved neoadjuvant therapy in HER2‑positive breast cancer: A retrospective study.

Pyrotinib is a novel irreversible tyrosine kinase inhibitor targeting the human epidermal growth factor receptor (HER), whose efficacy in treating metastatic HER2-positive (HER2) breast cancer has been confirmed. The present study aimed to explore the efficacy, safety and prognostic factors of pyrogenic-involved neoadjuvant therapy in patients with HER2 breast cancer. A total of 49 patients with HER2 breast cancer who received pyrotinib-neoadjuvant therapy were recruited. All patients received pyrotinib plus chemotherapy with or without trastuzumab neoadjuvant treatment for six cycles (21 days/cycle). Concerning the clinical response, 4 (8.2%), 36 (73.4%) and 9 (18.4%) patients achieved complete response, partial response and stable disease after 6-cycle pyrotinib-neoadjuvant treatment, respectively; the objective response rate and disease control rate reached 81.6 and 100.0%, respectively. Concerning the pathological response, 23 (46.9%), 12 (24.5%), 12 (24.5%) and 2 (4.1%) patients were evaluated as Miller-Payne grade 5, 4, 3 and 2, respectively. In addition, 23 (46.9%) patients achieved pathological complete response (pCR) in the breast tissue, 40 (81.6%) patients achieved pCR in lymph nodes, while 22 (44.9%) patients obtained total pCR (tpCR). Further multivariate logistic regression analysis demonstrated that pyrotinib plus trastuzumab and chemotherapy (vs. pyrotinib plus chemotherapy) was independently correlated with increased tpCR (P=0.048). The most frequent adverse events included diarrhea (81.6%), anemia (69.4%), nausea and vomiting (63.3%), and fatigue (51.0%). The majority of the adverse events were mild and controllable. In conclusion, pyrotinib-neoadjuvant therapy presented optimal efficacy and mild toxicity in patients with HER2 breast cancer, whose efficacy was affected by the combination treatment with trastuzumab.