Preoperative Needle Biopsy of Sentinel Lymph Nodes Using Intradermal Microbubbles and Contrast-Enhanced Ultrasound in Patients With Breast Cancer

Abstract

OBJECTIVE: The purpose of this study was to assess whether sentinel lymph nodes (SLNs) that undergo targeted needle biopsy after identification by contrast-enhanced ultrasound (CEUS) using intradermally injected microbubbles results in more node-positive breast cancer patients being diagnosed preoperatively. Furthermore, we sought to determine whether the addition of CEUS to gray-scale sonography of the axilla reduces the number of patients having axillary lymph node (ALN) dissection as a second procedure. SUBJECTS AND METHODS: Intradermal microbubble injection was performed in 136 breast cancer patients who had no abnormal ALNs on routine gray-scale axillary sonography. When an enhancing ALN was visualized, percutaneous sonography-guided fine-needle aspiration cytology or core needle biopsy was performed. Depending on the biopsy results, patients underwent SLN biopsy or ALN dissection. If the putative SLN biopsy was positive or a biopsy tract was seen in the excised SLN, the procedure was defined as successful. RESULTS: SLNs were identified and biopsied in 126 of the 136 cases (93%). Seventeen patients had positive sonography-guided biopsy results (13%) and were treated with immediate ALN dissection. In seven patients, the biopsied node was the only positive node. The remaining 109 patients underwent SLN biopsy. In nine cases (8%), a positive lymph node was identified. Four of these false-negative cases had only micrometastases. CONCLUSION: SLNs can be identified and biopsied using CEUS to increase the accuracy of preoperative axillary staging. If the needle biopsy result is negative, conventional SLN biopsy is indicated.