(P 386) RADIO-GUIDED SURGERY FOR NONPALPABLE SOFT-TISSUE SARCOMAS

Objective: To evaluate the feasibility and results of a series of patients with soft tissue sarcomas resected using intraoperative radio-guided surgery.

Methods: This is a retrospective and descriptive study on a prospective database. All patients with nonpalpable soft tissue sarcomas treated between 2005 and 2025 who underwent radio-guided surgery were included. Technique: within 24 hours before surgery the patients were injected in the peritumoral area with 99mTc-labeled colloid via ultrasound guidance. During surgery, the tumor area was localized using a hand-held gamma probe in order to avoid direct visualization of the tumor. We evaluated tumor characteristics, location, history of previous treatments (surgery and/or radiotherapy), resection margins and recurrence.

Results: We performed a radio-guided surgery on 10 patients with localized soft tissue sarcomas. The female:male ratio was 8:3. The median age was 58 years (IQR 50-65 years). According to histology we observed 3 mixofibrosarcomas, 1 malignant peripheral nerve sheath tumor, 1 undifferentiated pleomorphic sarcoma, myxoid liposarcoma, 1 sinovial sarcoma, 1 solitary fibrous tumor, 1 leiomyosarcoma, 1 chondrosarcoma. All tumors were located in the lower extremities and were deep to the superficial fascia. Previous radiothearpy has been administered in 8 patients. The median tumor size was 2.7cms (IQR 2-3.5cms). Median operative time was 171min (IQR 155-180min). Intraoperative localization was successful in 100% of patients. Complete resection was achieved in 9 patients, 1 patient presented multiple nodules during surgery that were not detected by ultrasound at the moment of the injection. Local recurrence after radio-guided resection was observed in 2 patients (20%). There were no complications related to the 99mTc-labeled colloid use. There were 2 patients with grade ≤2 Clavien-Dindo postoperative complications (in both cases it was a wound infections treated with antibiotic).

Conclusion: In our experience, radio-guided tumor resection is a feasible and safe procedure than can be performed in patients with nonpalpable and deep sarcomas. The local control rate (80%) was similar to that obtained in conventional surgery.