Intraoperative Localization Using an Implanted Radar Reflector Facilitates Resection of Non-Palpable Trunk and Extremity Sarcoma

Background: Resecting non-palpable soft tissue tumors presents a unique challenge, particularly with recurrent disease in which surrounding tissue has been surgically manipulated and often irradiated. SAVI SCOUT is a radar-based localization device that was developed for breast tumor localization and was recently FDA-approved for localization of soft tissue tumors. Application of this technology to soft tissue sarcoma has not been previously reported.

Methods: We assembled a single-institution retrospective case series of patients with trunk and extremity sarcomas resected by five sarcoma surgeons using SAVI SCOUT from December 2018 to May 2020. Reflectors were placed preoperatively using image-guidance, and the radar detector was used intraoperatively to localize the target lesion. Clinical variables were abstracted from the electronic medical record including treatment history, pathology, and early oncologic outcomes. Using a focused review, we compared margin status and recurrence rates with previously published cohorts.

Results: Ten SAVI SCOUT-localized sarcoma resections were performed. Eight were for locally recurrent disease, of which seven (83%) had prior radiation. The remaining lesions became non-palpable after neoadjuvant chemotherapy. SAVI SCOUT facilitated resection in all cases with a margin-negative resection rate (77%) comparable to prior cohorts. In this high-risk population with a median follow-up of 14 months, only one patient recurred locally 7.5 months after SAVI SCOUT-localized resection, requiring re-resection.

Conclusion: SAVI SCOUT technology facilitated resection of non-palpable recurrent sarcoma of the trunk and extremities in all ten cases attempted. In a high-risk patient population, the pattern of recurrence has been primarily distant with one instance of local tumor recurrence.