Evaluation of Two Techniques for the SLN Detection in BC Patients

The principal objective of this study is to evaluate the detection rate, the false negative rate and the overall accuracy of the lymphofluoroscopic research of the sentinel lymph nodes after periareolar injections of Indocyanine Green (ICG) in combination and in comparison with our classical intramammary and peritumoral injections of 99mTc-HSA-Nanocolloids in patients with breast cancer. These patients are currently out of the inclusion criteria and still undergo systematically complete axillary node dissection.

In this study (which would include at least 200 patients over a period of 2 years, with at least 100 patients after neoadjuvant chemotherapy) the involved surgeons would continue to perform complete axillary node dissections.

The radioactive SLN would be retrieved ex vivo in the axillary piece (with the gamma probe, after intramammary and peritumoral injections of radiocolloids the day before the surgery, or at least 3 hours before, with scintigraphic preoperative images as already performed routinely for patients described in the introduction 1 of this letter). These radioactive lymph nodes would thereafter been controlled for their possible fluorescence (with our fluorescence camera and after periareolar injection of ICG in the operating room just before the surgery). Finally, in the service of Pathology, all the lymph nodes found by the pathologist in the axillary piece will be controlled for their possible fluorescence.

With this approach, the surgeon will not have to search for SLN and the operative duration will not be extended.

Secondary objectives:

The current literature about the results of SLNB technique has not yet considered the influence of the addition of SPECT-CT imaging (standard approach in our institute since more than 3 years) to planar imaging. In this study, we propose to analyse in a prospective manner the contribution of SPECT-CT: contribution of the analysis of the signal intensity of active lymph nodes on SPECT slides to define a resection threshold corresponding to lymph nodes at risk of being pN+, accuracy for the anatomic localization, better accuracy of the number of SLN on the SPECT-CT versus planar image, better definition of the number of lymph nodes (to be analysed on the CT) covered by a radioactive spot (we have already observed 3 adjacent lymph nodes under one only active spot).

In this last case, such spots covering several lymph nodes would be analysed for the possible fluorescence of each lymph node.

The fluorescence of the detected lymph nodes will be analysed semi-quantitatively and related to their pN+ characteristics (pNi, pNµ, pN1, pNmacro). This first analysis may have major implications when our surgeons will perform an in vivo research of fluorescent SLN (see also Bourgeois et al. 2003).

Finally, we propose to analyse the kinetic and the vascular characteristics (aspects of the vessels on the images) of ICG migration from its injection point to the axilla. We will try to define possible predictive parameters of extended and/or macroscopic involvement of axillary lymph nodes.