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Updated: Jun 26, 2026
Electromagnetic Navigation Transthoracic Nodule Localization for Minimally Invasive Thoracic Surgery
Published on: May 4, 2022
Nodal localisation with magnetic seed in patients with stage III melanoma receiving neoadjuvant immune checkpoint
Ellen Krabbe1, Anne Huibers1, Lars Ny2
1Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Surgery, Sahlgrenska University Hospital, Gothenburg, Region Västra Götaland, Sweden.
Introduction:
Neoadjuvant immune checkpoint inhibitors (ICIs) have been established as standard care for patients with resectable macroscopic stage III melanoma. In these patients, therapeutic lymph node dissection (TLND) has been performed. However, the PRADO trial showed that TLND and also adjuvant treatment could be omitted in patients with a major pathological response (MPR) in the index lymph node. The aim of this study was to evaluate the feasibility of using a magnetic seed (Magseed®) to localise the index node for selective removal and analysis in patients with stage III melanoma receiving neoadjuvant ICIs.
Methods:
Twenty consecutive patients with resectable stage III melanoma and planned TLND after neoadjuvant ICIs were included. Magseed® was placed under ultrasound guidance at start of treatment. Index lymph node (ILN) resection was performed concurrently with TLND, 6-8 weeks after treatment initiation. A handheld magnetometer (Sentimag®) was used to localise the marked lymph node. This index lymph node was analysed separately for pathological response and seed presence.
Results:
Transcutaneous and intraoperative localisation was successful in all 20 patients. In 19 of 20 (95%) patients, the seed was present in the surgical specimen after resection. In one patient the Magseed® dislocated during surgery. In all eleven patients with evaluable specimen in both index lymph node metastasis and additional LN metastases, the pathological response was concordant between the index and the additional lymph nodes.
Conclusion:
In this feasibility trial evaluating Magseed® as a marker for ILN resection in patients with stage III melanoma, all marked lymph nodes were successfully localised.
