NTTS 2017

There has been continued interest by several groups in expanding the role of sentinel lymph node dissection (SLND) for biopsy confirmed node-positive patients who receive neoadjuvant chemotherapy as a way to restage the axilla in hopes of sparing women who convert to node-negative status from the morbidity of complete nodal dissection although previous trials have shown higher than desirable false-negative rates (FNR). While sentinel lymph node dissection alone may not accomplish this goal, there are novel techniques, such as TAD which utilizes a 125I radioactive seed localization of known previous marked nodal metastases with concurrent SLND. Placement of a radioiodine seed in known axillary metastatic nodes was originally described by investigators in the Netherlands. Multiple techniques have been described using tattooed nodes and wire-localization techniques. Caudle et al. described the initial trial results from MD Anderson using targeted axillary dissection in the Journal of Clinical Oncology in 2016 and the technique now allows for reliable nodal staging after chemotherapy. Of 208 patients enrolled, 191 underwent axillary lymph node dissection (ALND) with residual disease identified in 120 (63%). The clipped node revealed metastases in 115 resulting in a FNR of 4.2% (95% CI 1.4-9.5) for the clipped node. In patients undergoing SLND and ALND (n=118), the FNR was 10.1% (95% CI 4.2-19.8). Adding evaluation of the clipped node reduced the FNR to 1.4% (95% CI 0.03-7.3) (p=0.03). The clipped node was not retrieved as a SLN in 23% (31/134) including 6 with negative SLNs but metastasis in the clipped node. This explains why it is essential to identify, excise, and examine the specific biopsied initial node with the documented metastases for this technique to an accurate staging method. Updated results at the 2017 SSO Symposium were presented by Caudle et al and TAD followed by ALND has now been performed in 176 patients with a FNR of 2.4% (3/127, 95% CI 0.05-6.8). As a result of these trial results we selectively utilize TAD and perform completion axillary dissection only when metastases is identified in the clipped and or positive SLN. Selection of appropriate patients for this new technique will be presented.