Evaluation of clinical and pathological responses of HER-2 positive locally advanced breast cancer patients after neoadjuvant therapy and surgery

Purpose: This study aimed to compare the effectiveness and toxicity of neoadjuvant dual Human epidermal growth factor receptor-2 (HER-2) blockade combined with chemotherapy in advanced breast cancer. Materials and Methods: Patients with HER2-positive breast cancer who received trastuzumab (T)+ pertuzumab (P) with weekly neoadjuvant paclitaxel or docetaxel were included in the study. Patients’ age, clinical stage, histological reports, ki-67 index, toxicity profiles, and the state of the pathological and radiological response following neoadjuvant therapy were evaluated. Results: All 40 patients were women (mean age 50.9) and the overall rate of pathological complete responses was 62.5% (25/40). The rates of non-responsive patients and grade 2 neuropathy were statistically significantly higher in the group receiving P+T+Weekly Paclitaxel. When SUV values were analyzed based on hormone positivity, it was found that they decreased dramatically in both groups and were statistically significant. The logistic regression analysis developed to predict the precise response status to therapy was found to be significant. Conclusion: When comparing the agents used in dual HER-2 targeted therapies, patient response rates and toxicity profiles may differ. Ductal carcinoma in situ (DCIS) and molecular subtype were found to be significant variables in the developed logistic regression model.