Introduction: Identifying predictors of pathological complete response (pCR) and long-term outcomes after neoadjuvant treatment for breast cancer is needed to individualize treatment and patient monitoring. This study aimed to investigate clinicopathological factors affecting pCR and long-term outcomes in stage III breast cancer patients receiving a dose-dense neoadjuvant regimen.
Methods: This is a retrospective study including patients with stage III breast cancer who received neoadjuvant chemotherapy consisting of doxorubicin 60 mg/m² plus cyclophosphamide 600 mg/m², followed by paclitaxel 175 mg/m² every two weeks at Vietnam National Cancer Hospital and Hanoi Oncology Hospital between January 2015 and December 2022. Logistic and Cox regression were used to investigate the association between clinicopathological factors and pCR and long-term outcomes, respectively.
Results: A total of 211 patients were included in the study. Univariate analysis found an association of pCR with clinical tumor (cT) stage, grade, hormone receptor status, HER2, Ki67, and St. Gallen classification. Multivariate analysis identified several predictors of pCR: cT stage (cT3/T4 vs cT1/T2: OR: 0.3; p = 0.01); grade (grade 3 vs grade 1-2: OR: 1.6; p = 0.035); and hormone receptor status (nega-tive vs. positive: OR: 2.9; p = 0.011). Two independent prognostic factors for event-free survival (EFS) were identified: hormone receptor status (negative vs. positive: HR: 2.1; p = 0.044) and pCR (No pCR vs. pCR: HR: 3.0; p = 0.018). Hormone receptor status was also the only independent prognostic factor for overall survival (OS) (negative vs. positive: HR: 2.6; p=0.039).
Conclusion: Low cT stage, grade 3, and hormone receptor-negative status were independent predictors of pCR. Hormone receptor-positive status and pCR were independent prognostic factors for better EFS, while hormone receptor-positive status was the only independent prognostic factor for better OS.
Keywords: Breast cancer; EFS; OS; dose-dense neoadjuvant; pCR.