Magnetically Guided Localization Using a Guiding-Marker System® and a Handheld Magnetic Probe for Nonpalpable Breast Lesions: A Multicenter Feasibility Study in Japan

Abstract

Accurate pre-operative localization of nonpalpable lesions plays a pivotal role in guiding breast-conserving surgery (BCS). In this multicenter feasibility study, nonpalpable breast lesions were localized using a handheld magnetic probe (TAKUMI) and a magnetic marker (Guiding-Marker System®). The magnetic marker was preoperatively placed within the target lesion under ultrasound or stereo-guidance. Additionally, a dye was injected subcutaneously to indicate the extent of the tumor excision. Surgeons checked for the marker within the lesion using a magnetic probe. The magnetic probe could detect the guiding marker and accurately localize the target lesion intraoperatively. All patients with breast cancer underwent wide excision with a safety margin of ≥5 mm. The presence of the guiding-marker within the resected specimen was the primary outcome and the pathological margin status and re-excision rate were the secondary outcomes. Eighty-seven patients with nonpalpable lesions who underwent BCS, from January to March of 2019 and from January to July of 2020, were recruited. The magnetic marker was detected in all resected specimens. The surgical margin was positive only in 5/82 (6.1%) patients; these patients underwent re-excision. This feasibility study demonstrated that the magnetic guiding localization system is useful for the detection and excision of nonpalpable breast lesions.

Updates and Debate Concerning Margin Adequacy and Management following Breast-Conserving Surgery

“…Meanwhile, a distance of 2 mm from the tumor margin was considered adequate for ductal carcinoma in situ (DCIS) [13][14][15][16][17][18]. Table 2 shows the overview of the methods used in non-palpable tumors to mark and remove the area of interest in conservative breast surgery [19][20][21][22][23][24][25][26][27][28].…”

“…In the case of infra-clinical, non-palpable tumors, it is possible to mark the area of interest with a hook wire placed through the tumor or the injection of a radiotracer (radioguided occult lesion localization -ROLL) [19]. Recently, the use of handheld superparamagnetic devices, such as MagSeed or the Guiding-Marker System, have provided an accurate and reliable localization method in BCS with favorable surgical outcomes [20][21][22] (Table 2). Other alternative, non-radioactive, wire-free localization methods, developed to increase the likelihood of complete tumor removal, include intra-operative ultrasound guidance [23], the LOCalizer radio-frequency identification (RFID) system [24,25], reflector-guided localization through SAVI-SCOUT [26,27], and fluorescence detection after intralesional indocyanine green (ICG) solution injection [113] or intravenous administration was used [28] (Table 2).…”

Exploratory Study of Superparamagnetic Iron Oxide Dose Optimization in Breast Cancer Sentinel Lymph Node Identification Using a Handheld Magnetic Probe and Iron Quantitation

“…These SLNs were probed using a magnetic handheld device developed by the Department of Electrical Engineering and Information Systems at the University of Tokyo [8]. This probe has also been applied to surgery for non-palpable breast lesions [15].…”

A Propensity Score Matched Analysis of Superparamagnetic Iron Oxide versus Radioisotope Sentinel Node Biopsy in Breast Cancer Patients after Neoadjuvant Chemotherapy

“…There are several limitations associated with the use of magnetic-guided surgery, including limited depth of detection and restricted use of metal instruments [38]. Moreover, since the magnetometer must seek out a small tracer collection point, the detection of SLNs by SPIO may be limited.…”