Ogün AYDOĞAN, Ahmet Ege SAKUR
Meandros Medical and Dental Journal - 2026;27(1):133-140
Objective: Pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) is a strong prognostic marker in breast cancer and may guide de-escalation of axillary surgery. This study evaluates breast, axillary, and overall pCR rates in initially node-positive patients and examines clinicopathologic predictors of response. Materials and Methods: We retrospectively reviewed 212 women with cytology-proven node-positive invasive breast cancer treated with NAC followed by surgery between February 2019 and July 2025. Breast pCR was defined as ypT0/Tis, axillary pCR as ypN0, and overall pCR as simultaneous clearance of invasive disease in both regions. Associations between pCR and clinical stage, tumor characteristics, and molecular subtypes were analyzed. Results: Breast, axillary, and overall pCR rates were 32%, 61%, and 29%, respectively. Axillary pCR exceeded breast pCR across all subtypes (p<0.001). HR-/HER2+ tumors showed the highest overall pCR (72.7%), whereas HR+/HER2- tumors had the lowest (15.9%). HER2 positivity and Ki-67 >=20% were significantly associated with higher response rates. Clinical T and N stage, focality, and multifocality were not significantly correlated with pCR. Axillary response was particularly high in HR-/HER2+ and HR-/HER2- subtypes. Conclusion: Molecular subtype is the strongest determinant of NAC response in node-positive breast cancer. The markedly higher axillary pCR rates compared with breast pCR highlight the possibility of axillary de-escalation, especially in HER2-positive and triple-negative disease.
