Magseed/magtrace-guided surgery in breast cancer- an institutional perspective

Abstract Background/Purpose: Superparamagnetic iron oxide (SPIO)-based techniques like Magseed and Magtrace offer alternatives for breast lesion and sentinel lymph node (SNL) localization. Magseeds placed under ultrasound guidance offer logistical and safety advantages compared to traditional wire-localization or radioactive seed placement. Further, Magtrace injection is a viable SNL-localization alternative that overcomes radiation safety, skin necrosis, and allergic reactions associated with traditional 99mTc colloid and Methylene blue/Isosulfan blue dyes. To evaluate the effectiveness of these techniques in surgical practice, we report the implementation of Magseed and Magtrace at Baylor St. Luke’s Medical Center. Methods: We retrospectively reviewed prospectively collected data from the 128 female patients undergoing Magseed/Magtrace procedures from October 2019 to December 2020. Demographics and clinical characteristics were summarized, and surgical outcomes analyzed including margin status, re-excision rates, post-operative breast and axilla complications, successful localization and detection rates. Results: Patients presented with varied diagnoses including 98 (77%) with invasive carcinoma, 21 (16%) with DCIS, and 9 (7%) with fibroadenoma, papillary, or other lesions. 50 patients (39%) underwent neoadjuvant therapy. Mean BMI at surgery was 27.33 kg/m2 (range, 17.80-48.65) and mean age was 57.26 years (range, 27-86). Breast density varied, 5 (4%) categorized as almost entirely fatty, 69 (54%) as heterogeneously dense, 12 (9%) as extremely dense, and 39 (30%) with fibroglandular density. For breast size there were 2 (2%) A cups, 13 (10%) B cups, 16 (13%) C cups, 10 (8%) D cups, 8 (6%) DD cups, 2 (2%) DDD cups, 1 (.8%) F cup, and 12 (9%) with in between breast size (A-DDD). 108 patients (84%) had on-table Magtrace injection and 52 (41%) had Magseed localization. 18 (14%) patients had Methylene blue/Isosulfan blue dye or Technetium-99 used with Magseed and/or Magtrace. There was a 100% (52/52) success rate of lesion localization using Magseed and a 94% (101/108) success rate of SLN detection using Magtrace. Magtrace brown skin staining occurred in 12/108 patients (11%). Breast complications occurred in 43 patients (34%), with bruising/hematoma in 30/43 (70%), seroma in 7/43 (16%), and infection in 4/43 (9%). Axilla complications occurred in 11 patients (9%): 5/11 (45%) had bruising/hematoma, 6/11 (55%) had seroma, and 1/11 (9%) had infection. Positive margins were seen in 11 (9%) patients with re-excision performed in 8 women (6%). Conclusions: Magseed and Magtrace are comparable to standard practices in terms of practicality, surgical implementation, and risk of surgical complications and re-excision, providing a rationale for the adoption of SPIO-based techniques. By putting these surgical techniques into practice and evaluating their success in excising a wide range of lesions and monitoring complications, there is possibility of introducing new, innovative techniques into a standardized clinical setting within surgical oncology. Magseed/Magtrace Procedures at BSLMCRaw NumberPercentageTechniquesMagtrace Only6047%Magseed Only1915%Magtrace + Magseed3124%Isotope1713%Blue Dye11%Skin Staining Post-Op.1211%Breast Complication4334%Wound Complication921%Infection49%Bruising/Hematoma3070%Seroma716%Patients with >1 complication49%Axilla Complication119%Wound Complication00%Infection19%Bruising/Hematoma545%Seroma655%Patients with >1 complication19%Re-excision Rate86%Histological TypesER+, HER2-7055%ER+10078%HER2+2016%TNB1310% Citation Format: Jessica Montalvan, Logan Healy, Huma Javaid, Ivan Marin, Brian Menegaz, Cary Hsu, Eric Silberfein, Elizabeth Bonefas, Stacey Carter, Alastair Thompson. Magseed/magtrace-guided surgery in breast cancer- an institutional perspective [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-20-06.