Role of sentinel lymphadenectomy combined with intraoperative ultrasound in the assessment of locally advanced breast cancer after neoadjuvant chemotherapy

Background: Sentinel node (SN) biopsy for patients with locally advanced breast cancer after neoadjuvant chemotherapy results in a lower detection rate and higher false-negative rate. The aims of the study were to explore the role of SN biopsy in these patients in Taiwan and to assess the role of intraoperative ultrasound examination of the non-SN level. Methods: We used a blue dye to identify the SNs in 127 patients with T3 locally advanced breast cancer initially treated with neoadjuvant chemotherapy. After SN biopsy, we used intraoperative ultrasound to explore the non-SN region for additional lymph nodes, followed by at least level II axillary dissection. All the SNs were evaluated histologically and immunohistochemically with anticytokeratin antibodies. All the non-SNs were examined by routine histology. Results: SNs were identified in 116 (91.3%) of 127 procedures. SN metastases were found in 64 cases (55.2%). Subsequent axillary dissection revealed tumor involvement of non-SNs in 40 (62.5%) of 64 cases. SN biopsy results had a sensitivity of 92.8%, a specificity of 100%, and a false-negative rate of 9.6%. Furthermore, intraoperative ultrasound detected suspicious malignant nodes in the non-SN level in 39 out of 40 cases, and detected 5 cases with non-SN metastases that had false-negative SN mapping. This technique decreased the false-negative rate of SN mapping from 9.6% to only 1.39% for these cases. Conclusions: SN biopsy results combined with intraoperative ultrasonography can accurately assess the non-SN status and help breast surgeons to decide whether subsequent axillary dissection is warranted after SN biopsy has been performed.