Intraoperative radiation therapy for high risk soft tissue sarcoma resection margins

Abstract

Background and objectives: External beam radiation (EBRT) can reduce local recurrence (LR) of soft tissue sarcomas (STS). The addition of intraoperative radiation therapy (IORT) can deliver high dose radiation boost to anticipated “high risk” margins while sparing adjacent structures.

Methods: A retrospective review (2004-2012) was performed of STS treated with surgical resection and IORT using HDR brachytherapy for anticipated close/positive margins.

Results: Twenty-four patients underwent 25 resections with IORT (1 patient had 2 separate recurrences). Tumors were primary in 72%, deep in 96% and intermediate/high grade in 84%. Tumor locations were extremity (44%), retroperitoneal (40%), truncal (12%) and neck (4%). Common histologies included pleomorphic (32%), liposarcoma (12%) and myxofibrosarcoma (12%).  Neoadjuvantly, 3 received chemotherapy and 13 received EBRT (median 50Gy; range 45-54).  Median IORT dose was 12Gy (range 10-17.5). Margins were microscopically positive in 20%; none were grossly positive. Adjuvantly, 5 received EBRT (median 46Gy, range 45-50) and 2 received chemotherapy.  Median follow-up was 20.1 months (range 2.7-96.4). No recurrences occurred at the IORT sites. Two-year LR free survival was 60.8% and disease specific survival was 84%.

Conclusion: Use of IORT at time of STS resection was effective at preventing LR at the treated site despite “high risk” features.