Primary retroperitoneal sarcoma is a type of rare cancer that developed in the connective tissues in the retroperitoneum. Though radiotherapy has proven to be effective against various extreme sarcomas, its efficacy against retroperitoneal sarcoma is not well-known. This study aims to examine the efficacy of preoperative radiotherapy with surgery in patients with primary retroperitoneal sarcoma.

This randomized, open-label, phase-3 clinical trial included a total of 266 patients with histologically documented, localized, primary retroperitoneal sarcoma. The patients were randomly assigned in a 1:1 ratio to receive either surgery alone (n=133) or preoperative radiotherapy followed by surgery (n=133). The primary outcome of the study was abdominal recurrence-free survival, along with the safety of the treatment.

During a median follow-up of 43.1 months, 128 patients (96%) in the surgery group had surgery, and 119 patients (89%) in the radiotherapy and surgery group had both radiotherapy and surgery. The median abdominal recurrence-free survival was 5.0 years in the surgery only group, compared with 4.5 years in the radiotherapy plus surgery group. The risk of adverse events was also higher in the radiotherapy-surgery group.

The research concluded that preoperative radiotherapy following surgery does not improve abdominal recurrent-free survival in patients with primary retroperitoneal sarcoma.