Pathological Complete Response with the 4AC-4THP Regimen in Neoadjuvant Treatment of HER2-Positive Breast Cancer: A Multicenter Retrospective Analysis in Vietnam

Purpose To assess the efficacy of the 4AC-4THP neoadjuvant treatment regimen in Vietnamese patients diagnosed with HER2-positive breast cancer. Methods A retrospective analysis of all 50 HER2 positive breast cancer patients received neoadjuvant therapy with 4AC- 4THP in three institutions in northern Vietnam from January 2016 to October 2024. Pathological response was evaluated using Chevallier’s criteria, in which complete pathological response was defined as yT0yN0 or yTisN0. Results Fifty eligible HER2 positive breast cancer patients treated with 4AC- 4THP regimens in a neoadjuvant setting at Hanoi Medical University Hospital, Vietnam National Cancer Hospital and Hanoi Oncology Hospital were included in the analysis. Median age was 41 (range 26–67 years). Of these 50 patients, 41 (82%) were premenopausal, while 9 (18%) were postmenopausal; 21 patients (42%) had hormone receptor-positive. The overall clinical complete response (cCR) rate for both tumors and lymph nodes was 56% (23 out of 50). The total pathological complete response (pCR) rate was 78% (39 out of 50). pCR was achieved in 40 out of 50 patients (80%) for breast tumors and in 32 out of 34 patients (94.1%) for lymph nodes. There was no significant association between pCR rate and age, tumor grade, hormone receptor status, and Ki-67 expression. Conclusion The 4AC-4THP regimen in neoadjuvant treatment for HER2-positive breast cancer has shown high therapeutic efficacy, achieving a pCR rate of 78.0%.