Potential benefits of neoadjuvant radiotherapy prior to "en bloc" compartmental resection of pure retroperitoneal liposarcomas.

Retroperitoneal liposarcomas(RPL) are rare malignant tumors, accounting for approximately 15% of soft tissue sarcomas and 0.07-0.2% of all cancers. The annual incidence is 0.5 to 1 per 100,000 individuals. Surgical resection is the only curative option, but recurrence rates are high, and the role of neoadjuvant radiotherapy(NRT) remains uncertain. This study aimed to assess the impact of preoperative NRT on overall survival(OS) and recurrence-free survival(RFS) in RPL patients undergoing compartmental resection, while identifying prognostic factors. A retrospective monocentric review of 94 patients with confirmed RPL treated between 2008 and 2022 was conducted. Forty-six patients received NRT, while 48 underwent surgery alone. Data on preoperative, intraoperative, and postoperative variables, including complications, recurrence, and survival, were analyzed. Kaplan-Meier analysis evaluated OS and RFS, and multivariate Cox regression identified independent prognostic factors. With a median follow-up of 46.5 months, OS did not significantly differ between the NRT and surgery-only groups (HR = 0.8; 95% CI [0.4-1.54], p = 0.48). However, RFS was significantly improved in the NRT group (HR = 0.41; 95% CI [0.21-0.83], p = 0.001), particularly in patients with dedifferentiated RPL (HR = 0.38; 95% CI [0.18-0.83], p = 0.015). Tumor rupture (HR = 5.5; p < 0.001) was a strong risk factor for recurrence, while NRT was a protective factor (HR = 0.3; p = 0.002). NRT did not improve OS but significantly enhanced RFS, particularly in dedifferentiated RPL cases. These results warrant further prospective studies to better define NRT's role in RPL management.