Clinicopathological factors that predict different responses of breast and axillary tumors to neoadjuvant chemotherapy and prognosis among patients with node-positive breast cancer: real world data

Background: Pathological complete response (pCR) has been proven to be related to prognosis. pCR can be further classified as pCR of the breast (bpCR), pCR of axillary lymph nodes (apCR) or pCR of both tumors. The aim of this study was to elucidate the outcomes and clinicopathological characteristics associated with different patterns of pCR. Methods: Patients with node-positive disease who received neoadjuvant chemotherapy between August 2009 and July 2016 and who achieved pCR in axillary lymph nodes, breast or both were included. Multivariate logistic regression was used to identify factors related to different patterns of pCR. Results: Among the 271 patients who were included in the study, 42.1% achieved total pCR, 46.1% achieved ApCR, and 11.8% achieved BpCR. Disease-free survival (DFS) was significantly better in the total pCR group than in the limited pCR groups throughout the entire cohort (p=0.042). Univariate and multivariate analyses indicated that patients with HR-negative disease and a high Ki-67 proliferation index were more likely to achieve total pCR. Patients with earlier T stage disease were more likely to achieve pCR only in the breast. Among patients who achieved limited pCR, there was no significant difference in terms of whether these patients received intensified adjuvant chemotherapy. Conclusions: Total pCR is still the best marker for predicting survival benefit in patients receiving neoadjuvant chemotherapy, and total pCR is more likely to be achieved in patients with HR-negative disease and a high Ki-67 proliferation index. T stage and N stage may predict apCR and bpCR, respectively.