Real World Evidence of Neoadjuvant Docetaxel/Carboplatin/Trastuzumab/Pertuzumab (TCHP) in Patients with HER2-Positive Early or Locally Advanced Breast Cancer: A Single-Institutional Clinical Experience

Purpose Docetaxel/carboplatin/trastuzumab/pertuzumab (TCHP) regimen is frequently used to treat early and locally advanced human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) in neoadjuvant setting. However, large-scaled realworld evidence did not exist. Materials and Methods We retrospectively reviewed medical records of patients with early or locally advanced HER2-positive BC who underwent neoadjuvant TCHP followed by curative surgery at Samsung Medical Center between January 2016 and August 2020. Results Of 447 patients, 316 (70.7%) received breast-conserving surgery and 131 (29.3%) received total mastectomy. In terms of neoadjuvant chemotherapy response, pathologic complete response (pCR) and residual cancer burden (RCB) score were analyzed. The rate of pCR was 64% a class of RCB 0 was observed in 65% of cases, RCB class I in 12%, RCB class II in 14%, and RCB class III in 2%. The 3-year event-free survival rate was 90.6%, BC with pCR occurred in 92.8%, and BC with non-pCR in 86.3% (p=0.016). In terms of distant metastasis, the 3-year distant recurrence-free survival rate was 93.5%; BC with pCR occurred in 95.9% and BC with non-pCR in 89.2% (p=0.013). Mucositis (85.2%), pain (83.2%), and diarrhea (70.5%) were the most common non-hematologic adverse events. In terms of hematologic adverse events, anemia (89.9%) was the most commonly observed adverse events followed by thrombocytopenia (29.8%). Conclusion Neoadjuvant TCHP therapy had a pCR rate of 64% and a 3-year event-free survival of 90% in real world experience. In terms of toxicity profile, anemia was frequently observed and adequate management including occasional transfusion was required.