Long-term results of two prospective trials of preoperative external beam radiotherapy for localized intermediate- or high-grade retroperitoneal soft tissue sarcoma

Background: The reported data on surgery plus radiotherapy for retroperitoneal soft tissue sarcomas (RPS) have been mostly from retrospective studies. We evaluated the long-term outcome of patients with operable RPS who were treated with protocol-based preoperative radiotherapy followed by complete surgical resection. Methods: Data from two prospective trials that included preoperative radiotherapy and surgery for patients with radiographically resectable RPS were combined to define long-term relapse rates and survival. Results: Seventy-two patients with intermediate- or high-grade RPS were treated with preoperative radiotherapy (median dose, 45 Gy; range, 18.0-50.4 Gy). Fifty-four patients (75%) had primary RPS, whereas 18 (25%) had recurrent disease. The median tumor size was 15.5 cm. Sixty-four patients completed the planned preoperative radiotherapy; 57 (89%) underwent laparotomy with curative intent, and 54 (95%) had a macroscopically complete (R0 or R1) resection. With a median follow-up of 40.3 months, 28 patients (52%) who received preoperative radiotherapy and underwent a macroscopically complete resection had recurrences. For the 54 patients who underwent R0 or R1 resection after preoperative radiotherapy, the 5-year local recurrence-free, disease-free, and overall survival rates were 60%, 46%, and 61%, respectively. The median overall survival has not been reached (>60 months). Conclusions: Patients with intermediate- or high-grade RPS treated with preoperative radiotherapy plus complete resection had a median survival >60 months. This compares favorably to historical data for similar patients treated with surgery alone.