Abstract
While some clinics have adopted abbreviated neoadjuvant treatment for HER2-positive breast cancer, there remains a shortage of comprehensive clinical data to support this practice. This is a retrospective, multicenter study. A total of 142 patients were included in the study who are HER2-positive breast cancer, aged ≤ 65 years, with left ventricular ejection fraction ≥ 50%, received neoadjuvant chemotherapy and underwent surgery at 10 different oncology centers in Türkiye between October 2016 and December 2022. The treatment arms were divided into 4-6 cycles of docetaxel/trastuzumab/pertuzumab for arm A, 4 cycles of adriamycin/cyclophosphamide followed by 4 cycles of taxane/TP for arm B. There were 50 patients (35.2%) in arm A and 92 patients (64.8%) in arm B. The median follow-up of all of the patients was 19.9 months (95% CI 17.5-22.3). The 3-year DFS rates for treatment arms A and B were 90.0% and 83.8%, respectively, and the survival outcomes between the groups were similar (p = 0.34). Furthermore, the pathologic complete response rates were similar in both treatment arms, at 50.0% and 51.1%, respectively (p = 0.90). This study supports shortened neoadjuvant treatment of HER2-positive breast cancer, a common practice in some clinics.