Abstract OT1-12-04: MRO PMS study - Intraoperative Specimen Magnetic Resonance Imaging System for Intraoperative Margin Assessment for Invasive Breast Cancer Using the ClearCoast™ System in Breast Conserving Surgery

Abstract Background Re-operation for involved margins in breast conserving surgery is associated with worse cosmetic outcome, increased medical costs, and patient anxiety. Therefore, obtaining negative margins during primary BCS is essential. In our prior non-interventional study, published in October 2021 (Thill M et al., J Surg Oncol 2021) the re-operation rate would have been reduced by 83% for invasive carcinoma, from 10% to 2%, and 50% for DCIS, from 30% to 15% re-operations, if results had not been blinded for the surgeon. The results suggested a potential reduction of the re-operation rate by up to 80% for patients undergoing BCS. Aim of the study Aim of our current study is to evaluate the interventional performance of the ClearCoast™ system (ClearCut Medical, Ltd.) in assessing surgical margins for IBC in breast conserving surgery (BCS) and reducing the re-excision rates. Material and Methods The ClearCoast™ system utilizes a diffusion-weighted-imaging (DWI) protocol to create 2D surface maps showing T2*, a MR parameter related to the tissue’s apparent diffusion coefficient (ADC), with a depth penetration of 1mm. ADC is a highly accurate differentiator for irregular versus normal tissue. From May 2021 till to date a prospective, non- blinded post marketing study (N=93), evaluating the performance of the ClearCoast™ system is currently ongoing in the Breast Centre at the AGAPLESION MARKUS KRANKENHAUS, Frankfurt, Germany. After standard evaluation with ultrasound and/or X-ray with or without wire or clip marking, the specimens are intraoperatively scanned with the ClearCoast™ system, and positive margins will lead to a direct re-resection by decision of the surgeon applying a simple T2* threshold to flag irregular tissue. The final histopathology results will be compared with the scan results on a margin per margin bases. In addition, the rates of recurrent surgery of the interventional group will be compared with those of a historical group on the bases of matched pairs. Primary endpoint of the study is the re-excision rates in both the interventional and the historical standard of care group. To date, 64 patients are enrolled in the trial, therefore, results of the trial may be presented at the SABCS 2022. Citation Format: Marc Thill, Katharina Kelling, Viviane van Haasteren, Tina Schnitzbauer, Petia Kiene, Anna Levin, Eyal Kolka, Zachi Peles, Sebastian Aulmann. MRO PMS study - Intraoperative Specimen Magnetic Resonance Imaging System for Intraoperative Margin Assessment for Invasive Breast Cancer Using the ClearCoast™ System in Breast Conserving Surgery [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT1-12-04.