Prognostic Value of Axillary Nodal Ratio after Neoadjuvant Chemotherapy of Doxorubicin/Cyclophosphamide Followed by Docetaxel in Breast Cancer: A Multicenter Retrospective Cohort Study

Purpose The purpose of this study is to investigate the prognostic value of lymph node (LN) ratio (LNR) in patients with breast cancer after neoadjuvant chemotherapy. Materials and Methods This retrospective analysis is based on the data of 814 patients with stage breast cancer treated with four cycles of doxorubicin/cyclophosphamide followed by four cycles of docetaxel before surgery. We evaluated the clinical significance of LNR (3 categories: low 0-0.20 vs. intermediate 0.21-0.65 vs, high 0.66-1.00) using a Cox proportional regression model. Results A total of 799 patients underwent breast surgery. Pathologic complete response (pCR, ypTO/isNO) was achieved in 129 patients (16.1%) (hormone receptor [HR] +/human epidermal growth factor receptor 2 [HER2]-, 34/373 [9.1%]; HER2+, 45/210 [21.4%]; triple negative breast cancer, 50/216 [23.1%]). The mean numbers of involved LN and retrieved LN were 2.70 (range, 0 to 42) and 13.98 (range, 1 to 64), respectively. The mean LNR was 0.17 (low, 574 [71.8%]; intermediate, 170 [21.3%]; high, 55 [6.9%]). In univariate analysis, LNR showed significant association with a worse relapse-free survival (3-year relapse-free survival rate 84.8% in low vs. 66.2% in intermediate vs. 54.3% in high; p < 0.001, log-rank test). In multivariate analysis, LNR did not show significant association with recurrence after adjusting for other clinical factors (age, histologic grade, subtype, ypT stage, ypN stage, lymphatic or vascular invasion, and pCR). In subgroup analysis, the LNR system had good prognostic value in HR+/HER2- subtype. Conclusion LNR is not superior to ypN stage in predicting clinical outcome of breast cancer after neoadjuvant chemotherapy. However, the prognostic value of the LNR system in HR+/HER2patients is notable and worthy of further investigation.