Magnetic dual application for sentinel lymph node detection and breast tumor localisation: The MAGDA—study
Olivia Näslund, Sarah Palm, Jenny Nyqvist Streng, Micael Oliviera Diniz, Sarah Båtelsson, Staffan Eriksson, Eirini Pantiora, Nushin MirzaeiAbstract
Introduction
Magnetic techniques for breast tumour localisation and sentinel lymph node (SLN) detection have demonstrated performance comparable to guidewire-based approaches. The MAGTOTAL trial established that 1.0 ml superparamagnetic iron oxide (SPIO) combined with Magseed localisation is safe and effective. However, evidence regarding the use of an ultra-low dose of 0.1 ml SPIO injected intradermally remains limited.
Methods
Patients scheduled for breast-conserving surgery with intradermal injection of 0.1 ml SPIO for SLN biopsy and Magseed localisation were identified retrospectively through operative registries at Sahlgrenska University Hospital and Västmanland Hospital. Approximately 400 patients were screened. Outcomes were compared with published results from the MAGTOTAL trial. Primary endpoints included re-excision rate, resection ratio (actual resection volume divided by optimal resection volume), and operative time.
Results
A total of 207 patients were included. The SLN detection rate was 96.7%, compared with 98.6% in the MAGTOTAL cohort. Re-excision was required in 3.9% of patients versus 2.9% in MAGTOTAL. The median resection ratio was 2.8 (IQR 1.6–5.1), compared with 1.9 (IQR 1.1–3.4). Median operative time was 81 min (IQR 65–100), compared with 76 min (IQR 59–101). Localisation failure occurred in 0.5% of patients versus 1.9% in the reference cohort.
Discussion
An ultra-low dose of 0.1 ml SPIO injected intradermally combined with Magseed localisation is feasible and yields comparable SLN detection rates, re-excision rates, and operative times to standard-dose protocols. The slightly higher resection ratio may reflect unadjusted preliminary data and will be further evaluated in the final analysis with adjustment for relevant confounding factors.