Choosing the optimal neoadjuvant backbone for HER2-positive breast cancer: A multicenter real-world comparison of AC-THP and TCHP in Vietnam.

58

Background: In the era of dual HER2 blockade, the optimal neoadjuvant chemotherapy backbone for HER2-positive breast cancer remains controversial, particularly regarding the use of anthracyclines. Multicenter real-world data comparing anthracycline-containing and anthracycline-free regimens in Asian and resource-constrained settings are limited. This study compared the efficacy and safety of AC-THP and TCHP in a multicenter real-world cohort in Vietnam. Methods: We conducted a retrospective multicenter real-world analysis of 140 patients with HER2-positive breast cancer treated with neoadjuvant chemotherapy across multiple oncology centers in Vietnam. Patients received either AC-THP (doxorubicin and cyclophosphamide followed by paclitaxel plus trastuzumab and pertuzumab; n = 52) or TCHP (docetaxel and carboplatin plus trastuzumab and pertuzumab; n = 88). Baseline clinicopathological characteristics, clinical tumor and nodal responses, pathological complete response (pCR), cardiac function, and treatment-related adverse events were analyzed. Results: Patients in the TCHP group were slightly older and more frequently presented with stage II disease. The clinical complete response rate was higher with AC-THP than with TCHP (53.8% vs 40.9%), with a higher clinical nodal response observed in the AC-THP group. pCR rates were comparable between regimens (71.2% with AC-THP vs 70.5% with TCHP). Distinct toxicity profiles were noted. TCHP was associated with higher rates of anemia (52.3% vs 36.5%), thrombocytopenia, and elevated liver enzymes, with grade 3-4 anemia occurring in 8% of patients, whereas no grade 3-4 anemia was observed with AC-THP. In contrast, AC-THP was associated with higher rates of neutropenia and febrile neutropenia. Reduction in left ventricular ejection fraction was infrequent and not clinically different between groups during neoadjuvant treatment. Conclusions: In this multicenter real-world Vietnamese cohort, anthracycline-containing and anthracycline-free neoadjuvant regimens achieved comparable pCR rates despite differing toxicity profiles. These findings support individualized neoadjuvant regimen selection based on patient characteristics and toxicity considerations, particularly in resource-constrained settings.

Key efficacy and safety outcomes.