Clinical Outcomes Among Major Breast Cancer Subtypes After Neoadjuvant Chemotherapy: Impact on Breast Cancer Recurrence and Survival

Background/aim: Prior studies have underlined the prognostic relevance of pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) in breast cancer. However, an accurate demonstration of treatment efficacy is dependent on its potential to predict long-term outcomes of recurrence and death, and this issue remains somewhat controversial. Patients and methods: One hundred and sixty-nine patients with breast cancer (BC) treated with NAC followed by surgery were enrolled in this retrospective study. After carrying out multivariable analyses, involving baseline characteristics (tumor stage, nodal status, histological grade, biological profile) and response status, we analysed the association between pCR and disease-free (DFS) and overall survival (OS) in various subtypes. Moreover, we investigated several residual disease-scoring combinations to check whether they could discriminate prognostic subsets according to their variable tumor range after NAC. Results: Overall, factors associated with pCR were non-luminal subtype (p<0.001), high grade (p=0.001) and HER2-overexpression (p=0.001). Residual tumor and nodal stage after NAC significantly correlated with DFS (p=0.007) and OS (p<0.001). Similarly, pCR after NAC showed significantly better DFS (p=0.01), particularly for HER2-positive (p=0.003), triple-negative (p=0.019) and HER2-positive Luminal B profiles (p=0.019). However, there was no statistical difference in the OS among patients who had PCR, compared to absence of pCR (p=0.40). Conclusion: Extent of residual disease and evidence of regression provide helpful prognostic details in BC patients treated with NAC. Achieving pCR after NAC is related with significantly better DFS, with the potential of maximized breast and axillary conservation based on clinical response. The distribution of expertise in a cross-disciplinary setting could provide safe and favourable prognosis, while improving cosmetic outcomes and quality of life.