Predictors of Nodal Pathological Complete Response in Asian Women with Stage II-III Node-Positive Breast Cancer

Background: Neoadjuvant chemotherapy (NAC) is increasingly used to treat node-positive (N+) breast cancer. Predictors of nodal pathological complete response (pCR) in Asian women are poorly described and there is variety in the management of the axilla after NAC. We evaluated predictors of nodal pCR and axillary management in a cohort of Asian N+ patients. Methods: Consecutive biopsy-proven N+ breast cancer patients treated with NAC were identified from the Shanghai Ruijin Hospital in China. Axillary lymph node dissection was performed on all patients, irrespective of the nodal response to NAC. Results: A total of 323 patients were included. Nodal pCR was achieved in 105 patients (33%), 15% of HR+/HER2- tumors, 38% of HR+/HER2+ tumors, 49% of HR-/HER2+ tumors, and 42% of HR-/HER2-tumors (p < 0.001). Factors associated with nodal pCR were (1) receptor status (HR+/HER2- [referent]: OR 3.42, 95% CI 1.43-8.16, p = 0.006 for HR+/HER2+; OR 4.19, 95% CI 1.85-9.50, p = 0.001 for HR-/HER2+; and OR 2.94, 95% CI 1.11-7.74, p = 0.029 for HR-/HER2-), (2) breast pCR (no pCR [referent]: OR 15.22, 95% CI 6.29-36.79, p < 0.001), and (3) absence of lymphovascular invasion (LVI [referent]: OR 9.04, 95% CI 2.09-39.18, p = 0.003). Conclusion: This study confirmed expected predictors of nodal pCR in Asian women and the benefit of NAC in downstaging the axilla independently of ethnicity.