BACKGROUND: To investigate the performance of contrast-enhanced ultrasound(CEUS) parameters of metastatic axillary lymph nodes (ALNs) before and after two courses of neoadjuvant chemotherapy (NAC) in breast cancer patients in predicting the efficacy of NAC. METHODS: A total of 41 postoperative breast cancer patients were selected. All patients underwent NAC, and ALN biopsy was positive before chemotherapy. Metastatic ALN was examined by CEUS before and after two courses of NAC. The CEUS parameters of metastatic ALNs before and after two courses of NAC were analyzed to determine the performance of CEUS parameters in predicting the efficacy of NAC in early stage. RESULTS: The NAC was effective for 28 cases and ineffective for 13 cases. There were no statistically significant differences in the CEUS parameters between effective NAC and ineffective NAC individuals before and after two courses of NAC. But, there were statistically significant differences in long diameter (LD), short diameter (SD), Peak intensity (Peak%) and area under the curve (AUC) between the effective and ineffective NAC patients after two courses of NAC. Receiver operating characteristic curve (ROC) analysis suggested the drop-out value of LD, SD, Peak% and AUC after two courses of NAC can be used as important indicators to evaluate the efficacy of NAC (p <
0.05). CONCLUSIONS: CEUS parameters of metastatic axillary lymph nodes (ALNs) before and after two courses of neoadjuvant chemotherapy (NAC) in breast cancer patients can predict the efficacy of NAC in early stage.