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.