Abstract PO1-22-11: Use of magnetic tracer and magnetic resonance imaging for sentinel lymph node detection after breast cancer recurrence and previous axillary surgery: The SentiRecur feasibility study

Abstract Background: Preoperative imaging increases the chance of finding the sentinel lymph node (SLN) in patients with previous axillary surgery. Current clinical routine for preoperative localization is Technetium (Tc99) and lymphoscintigraphy. An alternative method has been proposed using superparamagnetic iron oxide nanoparticles (SPIO) and non-contrast enhanced magnetic resonance imaging (MRI) of the axillae. In this feasibility study, SPIO+MRI was used in parallel with Tc99+scintigraphy for SLN localization. Methods: Twenty patients with recurrent breast cancer and previous axillary surgery at Sahlgrenska and Linkoping University Hospitals scheduled for SLN-biopsy will be included. All patients received Tc99+scintigraphy as per standard practice. In addition, a SPIO injection and bilateral axillary MRI was performed up to four weeks before surgery. Both preoperative and perioperative SLN-detection rates were studied. Rates and number of concordant SLNs were presented as percentages. Results: So far, ten patients received both SPIO+MRI and Tc99+scintigraphy. The SLN-detection rates per patient were 70% (7/10) for SPIO+MRI and 50% (5/10) for Tc99+scintigraphy, respectively. The perioperative SLN-detection rates per patient were 60% (6/10) for SPIO using the magnetic probe (SentiMagTM) and 30% (3/10) for Tc99 using a gamma-probe. In total, eleven SLNs were detected with SentiMag and four with gamma-probe. Of all SLNs, only four (36%) contained both SPIO and Tc99. Conclusion(s): Although preliminary, the results suggest that Tc99+scintigraphy may be replaced by the magnetic technique for detecting SLNs after earlier axillary surgery. The magnetic technique enables logistic advantages as tracer injection and SLN identification during a wider time frame. Table 1. Sentinel lymph node detection in patients with recurrent breast cancer Table 1. Sentinel lymph node detection in patients with recurrent breast cancer Citation Format: Eva VikhePatil, Kian Chin, Amalia SegerbardPlanoudis, Carlos Dussan, Henrik Leonhardt, Pontus Zaar, Pantelis Gialis, Fredrik Wärnberg. Use of magnetic tracer and magnetic resonance imaging for sentinel lymph node detection after breast cancer recurrence and previous axillary surgery: The SentiRecur feasibility study abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-22-11.