Neoadjuvant Chemotherapy in Patients with HER2-Negative Breast Cancer: A Report from Clinical Breast Cancer Registry of Iran.

Background: Neoadjuvant chemotherapy (NCT) has become an increasingly popular approach in management of breast cancer (BC). This study was conducted to evaluate the pathologic response and 36-month recurrence and survival rates of patients with human epidermal growth factor receptor 2 (HER2)-negative BC treated with different NCT regimens.

Methods: A total of 163 female patients with HER2-negative BC who received NCT during 2017-2020 were identified from the Clinical Breast Cancer Registry of Iran and entered the study. The prescribed NCT regimens included 4 cycles of doxorubicin plus cyclophosphamide, 4 cycles of doxorubicin plus cyclophosphamide followed by 4 cycles of paclitaxel, 4 cycles of doxorubicin plus cyclophosphamide followed by 4 cycles of docetaxel or 6 cycles of doxorubicin plus cyclophosphamide plus docetaxel (TAC).

Results: Thirty-two patients (19.6%) experienced pathologic complete response (pCR). TAC regimen, triple negative-BC and ki67>10% were significantly associated with increased pCR. The recurrence, overall survival (OS) and disease-free survival (DFS) rate at 36 months for all patients were 16.6%, 84.7% and 79.8%, respectively. Type of neoadjuvant regimen as well as age, hormone receptor status, Ki67, grade, clinical stage, type of surgery and pathologic response to chemotherapy did not significantly influence the survival and recurrence; however, TAC results in improved recurrence, OS and DFS rates.

Conclusion: This study provides further evidence that NCT is a viable treatment option for patients with HER2-negative BC. The TAC regimen resulted in a significantly higher pCR rate compared to other regimens, but did not result in a significant improvement in recurrence, OS and DFS and rates.