Use of Magtrace Bracketing for Excision of Lesion and Sentinel Lymph Node Localization in Breast Conserving Surgery for Breast Cancer

Breast cancer is the commonest cancer affecting women worldwide. Early breast cancer is treated surgically with wide local excision of tumor with axillary staging operations like sentinel node biopsy. Surgical adjuncts used in identifying and localizing the area for excision include metallic wire, radioactive or magnetic seeds and radiofrequency reflectors. These are placed in the lesion under image guidance by the breast radiologists, either on the day of surgery (wires) or prior (seeds). Bracketing localization is performed in case of multiple lesions or wide spread calcifications to aid the surgeons in performing wide local excision of all involved areas. This means placing multiple devices around the area of excision for accurate triangulation, which increase the costs significantly. Localization agents like radionucleotide labelled albumin, super paramagnetic iron oxide (SPIO) and colored dyes like methylene blue, isosulphane blue and indocyanine green are injected in the breast for identification of sentinel lymph nodes in the axilla. More recent studies have demonstrated successful use of SPIO in localization of small impalpable breast cancer lesions. This also raises the prospect of using SPIO for the dual purpose of lesion localization / bracketing and sentinel node biopsy. This study was designed to test this principle in patients requiring bracketing. This is a prospective proof-of-concept pilot study to evaluate the feasibility of SPIO (Magtrace®) as a single-agent solution for bracketing the excision area and localizing the sentinel lymph node for breast-conserving surgery. Patients with breast cancer requiring bracketing and sentinel node biopsy will be identified through multidisciplinary breast tumor board and invited to take part in the study. All patients who consent to participate will receive an injection of Magtrace® for bracketing (0.5ml each at four points around the excision area) one day before surgery under ultrasound guidance. Primary outcome will be successful localization of the Magtrace® signal in breast for bracketing and in the sentinel node, using a magnetic probe on the day of surgery. Clinical outcomes, complications and cost analyses will be performed as secondary outcomes. We anticipate a sample size of 35 patients to be recruited for the study.