Assessment for residual nodal disease after neoadjuvant chemotherapy with image-guided surgery.

Abstract

99 Background: Staging of breast cancer patients is enhanced by axillary ultrasound (US) and needle biopsy of abnormal lymph nodes (LN). When clips are placed in sampled metastatic LNs, they can be evaluated for nodal response to neoadjuvant chemotherapy (NCT). The goals of this study were to determine if pathologic changes in clipped LNs reflect nodal response to NCT and if targeted axillary dissection (TAD), which includes sentinel lymph node dissection (SLND) in addition to selective localization and removal of clipped LNs, could increase the accuracy of nodal assessment. Methods: This prospective study included patients with US-identified axillary metastases confirmed by needle biopsy with a clip placed in the sampled LN. After NCT, patients underwent axillary lymphadenectomy (ALND) with x-ray of the axillary contents to identify the clip-containing LN. In 38 patients, the clipped LN was selectively removed using wire (n=2) or I125seed localization (n=36) before ALND was performed. Five patients did not undergo ALND. The pathologic findings of the clipped LN were reported separately from the other nodes. Results: Ninety node positive patients were enrolled. Forty (44%) had a complete nodal response to NCT and 50 (56%) had residual disease. Pathologic evaluation of the clipped LN revealed metastases in 47/50 patients with residual disease, resulting in a false negative rate (FNR) of 6% (95% CI 1.3-16.6). In 52 patients who underwent SLND, the clipped LN was not a SLN in 23% (n=12). Thirty-one of these patients had residual disease; metastases were not seen in SLNs in 5 cases resulting in a FNR for SLND alone of 16% (95% CI 5.4-34). Evaluation of the clipped LN in addition to SLND improved the FNR to 3% (1/31, 95% CI 0.1-17). Thirty-one patients underwent TAD while an additional 7 had localization and selective removal of the clipped LN without SLND with one false negative result. Conclusions: US-guided marking of LNs with documented metastatic disease allows for their selective removal and improved pathologic evaluation for residual nodal disease. The FNR of SLND can be reduced by ensuring removal and evaluation of the clipped LN. TAD is technically feasible and allows for improved assessment of nodal response after NCT.