SentiNeo 2.0: Rationale for a multicenter study of pre-NAST axillary lymph nodes marking using SPIO in breast cancer
Kian Chin, Olivia Näslund, Sarah Palm, Eva Vikhe Patil, Ava Kwong, Helena Sackey, Staffan Eriksson, Hannah Floodeen, Ira Oikonomou, Anikó Kovács, Eva Molnar, Karolina Larsson, Michalis Kontos, Michael Alvarado, Andreas Karakatsanis, Roger Olofsson Bagge, Fredrik WärnbergAbstract
Introduction
Axillary lymph node status after neoadjuvant systemic therapy (NAST) remains a key prognostic factor. Chemotherapy-induced lymphatic fibrosis may affect the accuracy of lymphatic mapping after NAST. In the SentiNeo 1.0 pilot study, all 80 patients (40 cN0, 40 cN+) received an injection of superparamagnetic iron oxide (SPIO) before NAST, followed by technetium-99m (Tc99m) after NAST. Metastatic index lymph nodes (ILN) were marked with Magseed®. Seventy-six patients completed surgery. Sentinel lymph node (SLN) detection was higher with SPIO than Tc99m (86 versus 79%, P = 0.01), particularly in cN+ patients (81 versus 62%, P = 0.004). Detection of ILN was higher with Magseed® compared to Tc99m (97 versus 56%, P < 0.001). Tracer concordance was 79% based on Tc99m versus 49% based on SPIO (P < 0.001). SPIO identified more nodes with residual metastases (88 versus 28%, P < 0.001). Full results were published in Surgical Oncology Insight, volume 2, issue 1, March 2025, 100114. The current SentiNeo 2.0 study aims to validate these findings.
Methods
This is a prospective, multicenter, within-patient comparative study aiming to enroll 459 patients based on statistical power calculations. Key endpoints include SLN and ILN detection, tracer concordance, and residual nodal disease.
Results
Patient enrollment is ongoing across six sites (Gothenburg, Linköping, Karolinska University Hospital, Södersjukhuset, Västerås, and Hong Kong), with 26 patients enrolled as of April 2026. Additional centers have indicated interest in participation.
Discussion
SentiNeo 2.0 evaluates a novel approach to axillary staging with the potential to improve detection of clinically relevant lymph nodes after NAST and reduce understaging. Breast centers are invited to collaborate.