Ultrasound Accuracy in Detection of Metastatic Axillary Lymph Nodes in Breast Cancer after Neoadjuvant Chemotherapy

Background: In the present paper, the main diagnostic tool for re-evaluation of axillary lymph node involvement and planning of surgery after neoadjuvant chemotherapy (NAC) is ultrasound whose accuracy we aimed to determine herein. The high precision of ultrasound in diagnosis of metastatic axillary lymph nodes in untreated patients is well known; however, its worth in patients who received NAC is highly controversial.Method: We enrolled 165 breast cancer patients receiving NAC in this retrospective cohort study. They all had undergone post-NAC ultrasound done before surgery. The ultrasound reports were reassessed and validated by a breast radiologist. Finally, the histopathology reports were compared to those of the ultrasound. Results: Among 165 surveyed post-NAC ultrasounds, 53 women had positive results and 112 had negative results. Pathology and ultrasound reports were accordant in 93 women and adverse in 112 others. The false negative rate of post-NAC axillary ultrasound was calculated as 60.6%. The sensitivity and specificity of post-NAC AxUS were 39.4% and 79%, respectively. After NAC, there were certain changes in ultrasound reports from positive to negative in 50% and pathologic complete clearance was observed in just 28% of the women who were initially clinically lymph node positive.Conclusion: Ultrasound was not found to be an accurate and appropriate tool for evaluation of axillary lymph node involvement in breast cancer patients who receive NAC. By changing the primarily established surgical plan from ALND to SLNB, based on the ultrasound findings, patients may remain undertreated. Furthermore, the axillary nodes pathologic clearance after NAC was observed in less than one third of the women who were initially clinically node positive; accordingly, surgeons should be cautious about the optimum response of axillary metastatic lymph nodes to NAC.