Abstract P4-07-02: Concordance rate of 99mTc and ICG/near-infrared light detected sentinel-symphnodes in primary breast cancer

Abstract Background: Sentinel lymph node biopsy (SLNB) by 99mTechnetium +/- patent blue has been long-time standard in SLN detection. However, the lack of nuclear sources, limited availability of nuclear medicine departments in some health providers and cost issues have led to the development of other techniques. ICG labelling and detection by near-infrared light is one of these techniques which empower surgeons to schedule their surgery independently from these prerequisites. Patients and methods: We conducted a prospective study to evaluate the concordance rate of ICG-fluorescence and 99mTc for sentinel lymph node detection of primary breast cancer. Patients, aged 18 - 80 years, with unilateral or bilateral, unifocal or multifocal/ multicentric primary breast cancer without signs of metastases were eligible for this study. ECOG status of 0-2 and life expectancy > 1 year was required. Tumor stages included are a) Tis (>= 4 cm) b) T1 c) T2 and d) T3. We applied both sentinel lymph node labelling (99 mTc and ICG) in the same patient and compared the concordance of both methods. Results: 275 pateints were elgible for interims analysis. For the first sentinel lymph node, we detected a concordance rate for both methods of 91,7 % , for the second sentinel lymphnode 81 %. 3 and 6 additional SLN were detected as first and second SLN by ICG which would not have been detected by 99mTc. After neoadjuvant chemotherapy, all sentinel lymphnodes have been detected by ICG. Conclusion: SLNB by ICG near-infrared light is a valid alternative for radioactive labelled SLN, however does reveal different SLNs as the second SLN: After neoadjuvant chemotherapy, ICG was able to detect all SLNs. Citation Format: Peter Kern, Bittner Ann-Kathrin, Kimmig Rainer, Mokas Stefanos, Hoffmann Oliver. Concordance rate of 99mTc and ICG/near-infrared light detected sentinel-symphnodes in primary breast cancer [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P4-07-02.