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Background and Objectives: The standard preoperative technique for localizing non-palpable breast lesions is wire localization (WL). Radioactive seed localization (RSL) has been described as an alternative approach to address the number of clear disadvantages associated with WL. Yet, despite its proven advantages, the adoption of RSL has been impacted by considerable regulatory requirements for the handling of radioactive materials. To advance the progress made with RSL and eliminate the issues associated with radioactive components, the SAVI Scout® surgical guidance system has been developed. The SAVI Scout surgical guidance system is an FDA-cleared medical device that utilizes passive non-radioactive electromagnetic wave technology to provide real-time guidance during excisional breast procedures. The purpose of this pilot study is to determine the safety and efficacy of the SAVI Scout system in localizing and directing the removal of non-palpable breast lesions during excisional biopsy and lumpectomy procedures. The preliminary results from two institutions are reported. Materials and Methods: Following a feasibility study using the SAVI Scout system in resected breast tissues ex vivo, Institutional Review Board approval was granted for both institutions for women with a non-palpable breast lesion requiring preoperative localization for excision. Participating patients underwent localization and excision with the SAVI Scout system, which consists of an electromagnetic wave reflective device (reflector), handpiece and console. Using mammographic or ultrasound guidance, the reflector was placed percutaneously up to 7 days prior to the scheduled excisional procedure. At surgical excision, the surgeon used the SAVI Scout handpiece to locate the reflector, which was removed along with the surrounding breast tissue. The console provides audible feedback of reflector proximity to the handpiece. Successful reflector placement, localization and retrieval were the primary endpoints. Results: After the first training case (data not used), a total of 17 patients have participated in the study to date. The reflectors were successfully placed with mammographic guidance in 9/9 patients and with ultrasound guidance in 8/8 patients. Reflectors were placed an average of 1.7 days (range 0-6 days) before surgery. Five patients underwent excisional biopsy and 12 patients had a lumpectomy. The intended lesion and reflector were successfully removed in 17/17 patients. Reflector migration did not occur and no adverse events occurred. Of the 14 patients in which final pathology is currently available, 6 patients had no invasive or in situ carcinoma identified, 4 had no tumor in the excision, and 3/4 patients with tumor had clear margins. One patient had a focally positive margin and was recommended for re-excision. Conclusions: The preliminary data show the SAVI Scout system to be a safe and effective tool for the localization of non-palpable breast lesions. Ongoing accrual to this pilot study will validate these findings with planned enrollment of a total of additional 50 patients in the next 60 days at up to 3 additional sites. Citation Format: Charles E Cox, Melissa Themar-Geck, Ronald Prati, Michelle Jung, Jeff King, Steven C Shivers. Pilot study of a passive non-radioactive electromagnetic wave technology to localize non-palpable breast lesions [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-16-10.

Objectives This study was a multicenter evaluation of the SAVI SCOUT(®) breast localization and surgical guidance system using micro-impulse radar technology for the removal of nonpalpable breast lesions. The study was designed to validate the results of a recent 50-patient pilot study in a larger multi-institution trial. The primary endpoints were the rates of successful reflector placement, localization, and removal. Methods This multicenter, prospective trial enrolled patients scheduled to have excisional biopsy or breast-conserving surgery of a nonpalpable breast lesion. From March to November 2015, 154 patients were consented and evaluated by 20 radiologists and 16 surgeons at 11 participating centers. Patients had SCOUT(®) reflectors placed up to 7 days before surgery, and placement was confirmed by mammography or ultrasonography. Implanted reflectors were detected by the SCOUT(®) handpiece and console. Presence of the reflector in the excised surgical specimen was confirmed radiographically, and specimens were sent for routine pathology. Results SCOUT(®) reflectors were successfully placed in 153 of 154 patients. In one case, the reflector was placed at a distance from the target that required a wire to be placed. All 154 lesions and reflectors were successfully removed during surgery. For 101 patients with a preoperative diagnosis of cancer, 86 (85.1 %) had clear margins, and 17 (16.8 %) patients required margin reexcision. Conclusions SCOUT(®) provides a reliable and effective alternative method for the localization and surgical excision of nonpalpable breast lesions using no wires or radioactive materials, with excellent patient, radiologist, and surgeon acceptance.

The current technique for locating nonpalpable breast lesions is wire localization (WL). Radioactive seed localization and intraoperative ultrasound were developed to improve difficulties with WL. The SAVI SCOUT surgical guidance system was developed to improve these methods. The SCOUT system is a non-radioactive, FDA-cleared medical device that uses electromagnetic wave technology to provide real-time guidance during excisional breast procedures. Consenting patients underwent localization and excision using an implantable electromagnetic wave reflective device (reflector) and a detector handpiece with a console. Using image guidance, the reflector was placed up to 7 days before the surgical procedure. The primary end points of the study were successful reflector placement, localization, and retrieval. The secondary end points were percentage of clear margins, reexcision rates, days of placement before excision, and physician comparison with WL. This study analyzed 50 patients. The reflectors were placed under mammographic guidance (n = 18, 36 %) or ultrasound guidance (n = 32, 64 %). Of the 50 patients, 10 (20 %) underwent excisional biopsy and 40 (80 %) had a lumpectomy. The lesion and reflector were successfully removed in all 50 patients, and no adverse events occurred. Of the 41 patients who had in situ and/or invasive carcinoma identified, 38 (93 %) had clear margins and 3 (7 %) were recommended for reexcision. These data suggest that the SCOUT system is safe and effective for guiding the excision of nonpalpable breast lesions and a viable alternative to standard localization options. A larger prospective, multi-institution trial of SCOUT currently is underway to validate these findings.