Clinical and Therapeutic Factors Vary by Prognosis in Patients with Pathological Complete Response After Neoadjuvant Therapy for Breast Cancer

Purpose: To determine clinical predictors of recurrence and metastasis in patients with pathological complete response (pCR) after neoadjuvant chemotherapy (NCT). Methods: Patients treated with NCT who achieved pCR (n=285) were classified into three groups according to pre-NCT clinical stage (cStage): group I (IIa-IIb), group II (IIIa), and group III (IIIb-IIIc). Survival was analysed using the Kaplan-Meier method. The relationships between clinicopathological factors and recurrence were determined using Cox regression analysis. Results: The median follow-up was 31 months. The 3-year disease-free survival and overall survival rates in groups I, II, and III were 92.7%, 87.8%, and 66.7% (P < 0.01) and 98.6%, 98.3%, and 90.6% (P=0.370), respectively. Lymph node status and tumour size were independent risk factors for recurrence and metastasis after NCT. In the human epidermal growth factor receptor 2-positive subgroup, advanced cStage and lymph node metastasis were associated with recurrence (P < 0.01). In the hormone receptor-positive subgroup, disease-free survival rates differed for cStages I-II compared to cStage III (P=0.049) and clinical node status 0-2 compared to clinical node status 3 (P=0.037). Conclusion: Pre-NCT cStage predicted the prognosis of pCR for different breast cancer subtypes. Patients with advanced cStage, lymph node metastasis, and large tumour sizes had a higher risk of recurrence or metastasis.