Sentinel Node Biopsy Using a Magnetic Tracer Versus Standard Technique: The SentiMAG Multicentre Trial

Abstract

The magnetic technique is a feasible technique for SLNB, with an identification rate that is not inferior to the standard technique.

160. Optimising magnetic sentinel lymph node biopsy in an in vivo porcine model

“…However, the false negative rate has been unacceptably high in studies of magnetic SLNB. Shiozawa et al [16] (would be good here to list how many patients, and maybe give this trial a name to -to be consistent with he other two) reported a false negative rate of 17 per cent using the magnetic technique and even the SentiMAG Multicentre Trial, [17] which was found to be non-inferior to the dual technique for SLN identification demonstrated a false negative rate of 8 per cent and 4 per cent for the magnetic and dual techniques respectively. The Central-European SentiMag Study [18] identified a lower false negative rate for the magnetic technique of 3 per cent versus 9 per cent for the standard radioisotope technique, inconsistent with the previous studies.…”

“…This suggests that current practice of using 2 mL of magnetic tracer as in the SentiMAG Multicentre Trial is excessive, [17] with SLNB being possible with much lower volumes. Our results demonstrate that the lowest volume of magnetic tracer injected of 0.06 mL resulted in a mean iron uptake of the excised SLNs of 25 per cent compared to less than 2 per cent for the maximal volume of 2 mL (P<0.001) (Fig.3c).…”

“…Once taken up by macrophages in the mononuclear phagocyte system of the lymphatics, the magnetic tracer is believed to be broken down and distributed across iron stores in the body. [15] The magnetic tracer can be detected intra-operatively using a handheld magnetometer [16][17][18].…”

“…[16][17][18] The largest trial, the SentiMAG Multicentre Trial, [17] recruited 161 patients (170 SLNB procedures) and found that the magnetic technique was non-inferior to the standard dual technique. This was confirmed by a later study, the Central-European SentiMag Study, [18] of 150 patients.…”

“…[7,19] All studies injected the magnetic tracer periareolarly after induction of general anaesthesia, with Shiozawa et al [16] injecting 1.6 mL Resovist (Bayer Health Care Osaka, Japan; 27.9 mg iron/mL), and the other two trials both using 2 mL Sienna+ (27mg iron/mL) diluted in 3 mL normal saline. [17,18] In order to make the magnetic technique a creditable alternative to the current dual technique, it is essential that we understand the behaviour of magnetic tracers from the injection site to distribution within the lymphatic basin. Outstanding issues include the optimal volume of magnetic tracer to administer and timing of injection prior to surgery.…”