Predictive factors of an axillary pathological complete response of node-positive breast cancer to neoadjuvant chemotherapy

Purpose The present study aimed to identify the predictive factors of an axillary pathological complete response (Ax-pCR) in patients with node-positive breast cancer who underwent neoadjuvant chemotherapy (NAC). Methods The present study included 219 patients who underwent NAC followed by curative surgery, including axillary lymph node dissection (ALND), for 221 breast cancers between January 2010 and April 2018. All patients were clinically and/or pathologically confirmed to be node-positive at the initial diagnosis. The predictive factors of Ax-pCR were analyzed using a chi-square test and multivariate logistic regression models. Results Ninety-five patients (43%) achieved Ax-pCR after NAC. The odds of achieving Ax-pCR were significantly improved when tumors were high grade (odds ratio [OR] 2.20, 95% confidence interval [CI] 1.00–4.84), estrogen receptor (ER) negative (OR 2.65 95% CI 1.23–5.70), ycN0 on ultrasound (US) imaging (OR 3.89, 95% CI 1.90–7.97), and showed a clinical complete response (CR) at the primary site after NAC (OR 4.22, 95% CI 1.59–11.27). Conclusions Ax-pCR was more likely to be achieved in patients who were diagnosed with ER-negative and high-grade breast cancer and those with ycN0 and clinical CR at the primary site after NAC than among others. Among these patients, those with initially cN1/N2 might be good candidates for a deescalated treatment strategy after NAC.