Reflector-Guided Localisation of Non-Palpable Breast Lesions: A Prospective Evaluation of the SAVI SCOUT® System

Abstract

Wire-guided localisation (WGL) has been the mainstay for localising non-palpable breast lesions before excision. Due to its limitations, various wireless alternatives have been developed. In this prospective study, we evaluate the role of radiation-free wireless localisation using the SAVI SCOUT® system at the London Breast Institute. A total of 72 reflectors were deployed in 67 consecutive patients undergoing breast conserving surgery for non-palpable breast lesions. The mean interval between deployment and surgery for the therapeutic cases was 18.8 days (range: 0–210). The median deployment duration was 5 min (range: 1–15 min). The mean distance from the lesion was 1.1 mm (median distance: 0; range: 0–20 mm). The rate of surgical localisation and retrieval of the reflector was 98.6% and 100%, respectively. The median operating time was 28 min (range: 15–55 min) for the therapeutic excision of malignancy and 17 min (range: 15–24) for diagnostic excision. The incidence of reflector migration was 0%. Radial margin positivity in malignant cases was 7%. The median weight for malignant lesions was 19.6 g (range: 3.5–70 g). Radiologists and surgeons rated the system higher than WGL (93.7% and 98.6%, respectively; 60/64 and 70/71). The patient mean satisfaction score was 9.7/10 (n = 47, median = 10; range: 7–10). One instance of signal failure was reported. In patients who had breast MRI after the deployment of the reflector, the MRI void signal was <5 mm (n = 6). There was no specific technique-related surgical complication. Our study demonstrates that wire-free localisation using SAVI SCOUT® is an effective and time-efficient alternative to WGL with excellent physician and patient acceptance.

The Evolving Role of Radiofrequency Guided Localisation in Breast Surgery: A Systematic Review

“…It has been found to be at least non-inferior to WGL in terms of successful localisation and margin positivity rates. In addition, the device was reported to have minimal MRI void artefacts (<5 mm), in addition to good surgeon, patient and radiologist acceptability [ 46 , 47 , 48 ].…”

“…We found no significant difference in re-excision rates when comparing Magseed with WGL [ 10 , 12 ]. However, our pooled analysis of SAVI SCOUT performance reported that the use of the device was associated with a significant reduction in the re-excision rates compared with WGL in subgroup analysis [ 9 , 11 , 46 ]. However, this requires further validation in adequately powered prospective studies.…”

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].…”

“…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).…”

Efficacy and Accuracy of Using Magnetic Seed for Preoperative Non-Palpable Breast Lesions Localization: Our Experience with Magseed

“…It can be deployed inside the lesions the day before surgery. The Savi-Scout system is another non-wire and non-radioactive alternative technique; it uses a micro-impulse infrared radar to localize the lesions and is particularly useful for patients that need MRI examinations during follow-up, without artifacts [ 5 ].…”