Background: To analyze toxicity, patterns of failure, and survival in 106 adult patients with soft tissue sarcomas of the extremity and the superficial trunk treated in a prospective controlled trial of combined Perioperative High Dose Rate Brachytherapy (PHDRB) and external beam radiotherapy (EBRT). Methods: Patients were treated with surgical resection and 16 Gy or 24 Gy of PHDRB for negative or close/positive margins, respectively. EBRT (45 Gy) was added postoperatively. Adjuvant chemotherapy was given to selected patients with high-grade tumors. Results: The median follow-up was 7.1 years (range, 0.6-16.0). Grade >= 3 adverse events were observed in 22 patients (20.8%), and grade >= 4 events in 14 patients (13.2%). No grade 5 events were noted. Multivariate analysis (p = 0.003) found that Grade >= 3 toxic events increased with increasing implant volume (TV100). Local control, locoregional control, and distant control rates at 5 and 10 years were 89% and 87%, 82% and 80% and 75% and 69%, respectively. Multivariate analysis (p = 0.024) found that positive margins correlated with decreased local control. Disease-free survival and overall survival rates at 5 and 10 years were 64% and 59% and 73% and 62%, respectively. In multivariate analysis, disease-free survival rates decreased with increasing tumor size (p = 0.0001) and inadequate margins (p = 0.024), and overall survival decreased with increasing tumor size (p = 0.001) and male gender (p = 0.039). Conclusions: The combination of conservative surgery, high-dose PHDRB, and EBRT produces adequate function and local control in the majority of patients with soft tissue sarcomas of the extremities and the superficial trunk, including a substantial percentage of cases with positive margins. Patients with larger tumors are at a higher risk of complications, treatment failure, and cancer-related death and require an individualized treatment approach. (C) 2019 Elsevier B.V. All rights reserved.