Evaluation of Novel Iron-based Lymphatic Mapping Agent, Magtrace, for Delayed Sentinel Lymph Node Biopsy (SLNB) in Ductal Carcinoma In-Situ (DCIS)

The standard surgical approach for all patients undergoing mastectomy for the treatment of non-invasive, ductal carcinoma in situ (DCIS) is to perform axillary lymph node staging through use of a traditional sentinel lymph node biopsy (SLNB) procedure where the lymph nodes that drain the breast first are removed at the time of mastectomy. This recommendation for traditional SLNB is due to the risk of finding invasive cancer during surgical evaluation of the mastectomy specimen and the inability to accurately map the lymphatic channels once the breast is removed. In a study by Herremans et al, the majority of traditional SLNBs were demonstrated to be unnecessary. By using Magtrace, a novel iron based lymphatic mapping agent, a delayed SLNB could eliminate these unnecessary traditional SLNBs. Magtrace, or superparamagnetic oxide (SPIO), was developed in 2018. Unlike traditional mapping agents of blue dye and technetium that clear the body within 24-48 hours, Magtrace remains in the lymph nodes for at least 4 weeks. Magtrace's ability to remain in the lymph node allows accurate mapping of the lymph nodes at the time of the mastectomy with the ability to return to the operating room for a delayed sentinel lymph node biopsy if invasive cancer is found on final pathology. This study will investigate whether the use of Magtrace will successfully allow patients with DCIS undergoing mastectomy to avoid undergoing SLNB.