Real-world Outcomes of Neoadjuvant Dual HER2 Blockade with TCHP in Early and Locally Advanced HER2-Enriched Breast Cancer: Experience from a South Indian Tertiary Oncology Center.

BACKGROUND: HER2-enriched breast carcinomas are biologically aggressive but highly responsive to targeted therapy. Data on the real-world effectiveness of neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab (TCHP) from Indian oncology practices remain sparse.

OBJECTIVES: To assess pathological complete response (pCR), treatment-related toxicities (CTCAE v5.0), and survival outcomes among patients with nonmetastatic HER2-positive breast cancer receiving neoadjuvant TCHP.

MATERIALS AND METHODS: A bidirectional observational analysis was conducted on 55 patients with HER2-positive nonmetastatic breast carcinoma who were treated at a tertiary oncology center. Patients received neoadjuvant TCHP followed by definitive surgery. Clinical response, radiological response, pCR, treatment compliance, toxicity, disease-free survival (DFS), and overall survival (OS) were evaluated. Statistical associations with pCR were analyzed using Fisher's exact test.

RESULTS: The median age of the patients was 47 years. Stage III disease was the most common (70.9%). Hormone receptor negativity was observed in 56% of the patients. Clinical complete response was achieved in 85% of the patients, whereas radiological complete remission occurred in 58%. A pCR was documented in 60% of the cohort. A significant correlation with pCR was observed for clinical response (p < 0.001), radiological response (p = 0.002), and uninterrupted treatment completion within 18 weeks (p = 0.013). Hormone receptor expression and baseline stage did not significantly influence pCR rates. Diarrhea and neutropenia were the predominant toxicities, whereas clinically relevant cardiotoxicity was not encountered. At a median follow-up of 29 months, the estimated 3-year DFS and OS were 95% and 97.2%, respectively.

CONCLUSION: Neoadjuvant TCHP demonstrated substantial pathological response rates, acceptable tolerability, and encouraging survival outcomes in HER2-positive breast cancer. Adherence to the planned treatment timeline significantly influenced therapeutic efficacy.