Interstitial brachytherapy for soft tissue sarcoma: A single institution experience

PURPOSE: Soft tissue sarcomas (STSs) are an uncommon, histologically diverse group of malignancies, which are primarily treated with surgery. Depending on location and grade, radiation therapy may be used as adjuvant treatment. In this single institution, retrospective series, we examine treatment outcome for STS treated with surgery and adjuvant interstitial brachytherapy (BTX). METHODS AND MATERIALS: Forty-three patients were treated from 1997 to 2005 with adjuvant BTX for primary or recurrent STS. Thirty-four patients were treated for primary and nine for recurrent disease in locations including upper and lower extremity, pelvis, superficial trunk, and retroperitoneum. Twelve patients had low-grade and 31 had high-grade tumors. Most patients had lesions larger than 5 cm. Patients with low-grade tumors received 2500 cGy with BTX, followed by 4500 cGy with external beam radiation therapy (EBRT). High-grade tumors were treated with BTX alone to 4500 cGy if they were considered resectable at the time of diagnosis. For concern about resectability with conservative surgery, patients received 4500 cGy EBRT preoperatively, followed by a 2500 cGy BTX boost. RESULTS: Median followup was 39 months (range, 12-120). Thirty-four patients were known to be alive at last followup. The overall local control rate was 88%; local control was 87% for high-grade tumors and 92% for low-grade tumors. Disease-free survival was 75% overall with 88% free from distant metastases. No patient with low-grade sarcoma developed distant metastasis. Overall survival was 79%. The rate of long-term musculoskeletal or neurologic toxicity >Grade 3 was 7%, with all but a single case occurring in patients treated with EBRT plus BTX. CONCLUSIONS: Adjuvant interstitial BTX seemed to provide acceptable local control with well tolerated treatment in patients with low- and high-grade STS.