Multinational retrospective analysis of neoadjuvant radiotherapy for primary retroperitoneal well-differentiated liposarcoma

A retrospective analysis by the Transatlantic Australasian Retroperitoneal Sarcoma Working Group evaluated neoadjuvant radiotherapy (RT) in patients undergoing surgery for primary retroperitoneal well-differentiated liposarcoma (pRP-WDLPS). The primary endpoint was cumulative incidence funtion (CIF) of local recurrence (LR) and the secondary endpoint was overall survival (OS). The impact of neoadjuvant RT on the CIF of LR was analyzed using a 1:2 propensity score matching (PSM). Among 582 patients from 24 sites undergoing surgery between 2002 and 2017, 72 patients (12%) received neoadjuvant RT. The 1:2 PSM group included 208 patients (66% surgery alone; 34% neoadjuvant RT plus surgery). With a median follow-up of 73 months, the CIF of LR with neoadjuvant RT plus surgery was 6% at 5 years and 10% at 8 years, compared with 26% and 33%, respectively, with surgery alone (OR 0.85; p<0.001). The overall survival rate with neoadjuvant RT plus surgery was 92% at 5 years and 80% at 10 years, compared with 84% and 71%, respectively, with surgery alone (HR 0.50; p=0.07). The authors conclude that neoadjuvant RT plus surgery was associated with a significant decrease in LR compared to surgery alone.