Role of Ultrasound in the Diagnosis of Lymph Node Status in Axillary Lymph Node Metastases in Breast Cancer undergoing Neoadjuvant Chemotherapy

Background:Axillary ultrasound (AUS) is one of the important bases for evaluating the axillary status of breast cancer patients. And it would be helpful for the reassessment of axillary lymph node status in these patients after neoadjuvant chemotherapy(NAC) and guide the selection of their axillary surgical options.The purpose of this study was to evaluate the diagnostic performance of ultrasound,and to find out the factors related to the outcome of ultrasound.Methods:In this retrospective analysis, 172 patients (one bilateral breast cancer) with breast cancer and clinical positive axillary nodes, were enrolled. After NAC, all patients received mastectomy and axillary lymph node dissection (ALND). AUS was used before and after NAC to assess the axilla status. Results:Of the 173 axillae, 137 (79.19%) had pathological metastasis after NAC. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of axillary ultrasound in this cohort were 68.21%, 69.34%, 63.89%, 87.96% and 35.38% respectively. Univariate analysis showed that primary axillary lymph node(ALN) short axis, progesterone receptors, hormone receptors, the tumor status after NAC, tumor reduction rate, ALN short axis after NAC, physical examination of axilla after NAC and pN impacted the results of AUS(P = 0.000 ~ 0.040). Multivariate analysis of the above indicators showed that ALN short axis after NAC and pN associated with AUS results independently. Conclusion:AUS can accurately assess axilla status after NAC in most breast cancer patients. If the short axis of ALN≥10mm and AUS negative, SLNB could be chosen. However, AUS cannot detect residual lymph node disease after NAC in a short axis of the ALN <10mm.