Feasibility and accuracy of sentinel lymph node biopsy after preoperative chemotherapy in breast cancer patients with documented axillary metastases

BACKGROUND. The feasibility and accuracy of sentinel lymph node (SLN) biopsy in patients with breast cancer after preoperative chemotherapy has been demonstrated in a number of large, single-institution studies. However, a relative contraindication to SLN biopsy after preoperative chemotherapy is the presence of axillary metastases at initial diagnosis. The objective of this study was to determine the feasibility and accuracy of SLN biopsy after preoperative chemotherapy in patients with documented axillary metastases at presentation. METHODS. Between 1994 and 2002, 69 patients who had axillary metastases identified by ultrasound-guided, fine-needle aspiration underwent SLN biopsy after treatment on prospective, preoperative chemotherapy protocols. All but 8 patients underwent axillary lymph node dissection (ALND). Those 8 patients either declined additional surgery or were offered enrollment in other institutional protocols. RESULTS. The median patient age was 49 years, and the median primary tumor size was 4 cm. The SLN identification rate was 92.8%. Thirty-one of 64 patients (48.4%) had successfully mapped, positive SLNs. Sixty-one patients underwent ALND, including 5 patients who did not have an SLN identified. In the 56 patients in whom a SLN was identified and an ALND was performed, 10 patients had a false-negative SLN (25%). CONCLUSIONS. SLN biopsy was feasible after preoperative chemotherapy, even in patients who initially presented with cytologically proven, lymph node-positive disease. However, the false-negative rate of SLN biopsy in this group of patients was much higher than that observed in clinically lymph node-negative patients. Based on the current results, the status of the SLN cannot be used as a reliable indicator of the presence or absence of residual disease in the axilla in this patient population.