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BRIEF RESEARCH REPORT article
Front. Oncol.
Sec. Genitourinary Oncology
Volume 15 - 2025 | doi: 10.3389/fonc.2025.1523038
Bimodal inguinal sentinel lymph node imaging using a radiation-free fluorescent magnetic hybrid tracer in penile cancer patients
Provisionally accepted
Bianca Michalik1Svenja Engels1Maximilian C. Otterbach2Martin H. Maurer2Friedhelm Wawroschek1
Alexander Winter1*- 1University Hospital for Urology, Klinikum Oldenburg, Department for Human Medicine, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Lower Saxony, Germany
- 2University Institute for Diagnostic and Interventional Radiology, Klinikum Oldenburg, Department for Human Medicine, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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Invasive lymph node (LN) staging is crucial for survival in penile cancer (PeCa) patients. To lower patient morbidity associated with radical inguinal lymphadenectomy, sentinel node biopsy (SNB) is recommended. Application of conventional radioactive/fluorescent tracers for sentinel node (SN) labelling is limited to centers with nuclear medicine or lacks pre-operative imaging. We introduce a radiation-free fluorescent magnetic hybrid tracer for bimodal inguinal SN imaging in PeCa patients. In three consecutive PeCa patients, the fluorescent magnetic hybrid tracer (50 µl indocyanine green, 5 mg/ml, in 1 ml superparamagnetic iron oxide nanoparticles) was peritumorally injected. SNs were visualized by magnetic resonance imaging (MRI). Intra-operatively, SNs were detected using a handheld magnetometer and a fluorescence camera. Concordance was determined between MRI and magnetometer-guided SNB and between magnetic and fluorescent SN labelling. MRI revealed 29 SNs (median 4.5, range 0-8 SNs/groin). Twenty-five LNs (median 4.5, range 0-9 LNs/groin) were resected, including 16 magnetically active and 17 fluorescent SNs (median 3, range 0-6 SNs/groin, either mode). MRI and magnetometer-guided SNB had 66% concordance, magnetic and fluorescence SN labelling 96%. The diagnostic accuracy of our approach has to be evaluated in larger patient cohorts. Our radiation-free SNB technique is feasible without the need for nuclear medicine, its associated additional effort and regulations.
Keywords: Fluorescence Imaging, Hybrid tracer, ICG, Penile Cancer, sentinel lymph nodes, SPION
Received: 05 Nov 2024; Accepted: 18 Apr 2025.
Copyright: © 2025 Michalik, Engels, Otterbach, Maurer, Wawroschek and Winter. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Alexander Winter, University Hospital for Urology, Klinikum Oldenburg, Department for Human Medicine, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Lower Saxony, Germany
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.