Abstract P1-01-02: The SentiMag study: Sentinel node biopsy with superparamagnetic iron oxide vs. radioisotope

Abstract Background: The SentiMag study compares the “gold standard” 99mTc with a new technique, which employs superparamagnetic iron oxide particles (SPIO) for localization of sentinel lymph nodes. Aim of this study is to investigate the potential equivalency of the SentiMag® technique in comparison to the gold standard of sentinel lymph node biopsy (SLNB). Materials and methods: In a prospective, multicentre and multinational 2-arm study, 150 patients with histologically verified breast carcinoma are examined. For comparison, SLNs are marked initially with radioisotope following a 1- or 2-day protocol. Additionally, SPIO (Sienna+®) is injected in the operation room by the surgeon at least 20 minutes before SLNB into the subareolar interstitial tissue, followed by 5 minutes massage. SLN-detection is carried out using a magnetometer (SentiMag®) and a gamma probe. Preparation and excision of lymph nodes is conducted using both techniques in a parallel manner. All lymph nodes marked with either tracer are excised. Results: Interim analysis of 138 patients resulted in a detection rate concordance per patient of 97% (134/138). An average of 1.9 (radioisotope) and 2.0 (SPIO) lymph nodes were collected per patient. Nodal detection rate was 92% (250/273) for the radioisotope vs. 97% (265/273) for the SPIO tracer with magnetometer detection. The proportion of pathologically positive lymph nodes was 38/250 (15%) vs. 39/265 (15%) for the radioisotope and the SPIO tracer respectively. All pathologically positive lymph nodes detected with the conventional technique (radioisotope) were also detected with the new technique (SentiMag®). Conclusions: The SentiMag® provides an easy technique which can be rapidly implemented into daily routine. Due to the simple handling, preoperative efforts can be reduced to a minimum. If further and consistent results prove its efficacy, this technique may ultimately replace the standard of care. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-01-02.</jats:p