Low and moderate grade retroperitoneal liposarcoma: Is adjuvant radiotherapy associated with improved survival in patients undergoing R1 resection?

Background: Few studies evaluate the efficacy of adjuvant radiotherapy (aXRT) in patients with retroperitoneal liposarcoma undergoing resection to histologically positive (R1) margins.

Methods: We queried the National Cancer Database to identify patients undergoing R1 resection for localized, large (>5 cm) low and moderate grade retroperitoneal liposarcoma between 2004 and 2016. Kaplan Meier method was used to compare overall survival (OS) for patients receiving aXRT to a 1:2 propensity-matched cohort of patients undergoing resection alone.

Results: A total of 322 (76.5%) patients underwent R1 resection alone, while 99 (23.5%) underwent resection followed by aXRT. The 99 receiving aXRT were successfully 1:2 propensity-score matched to 198 undergoing resection alone. There was no difference in 5-year OS between matched cohorts (69.7% vs 76.2%, p = 0.40).

Conclusions: In patients undergoing R1 resection of moderate- and well-differentiated retroperitoneal liposarcoma, use of aXRT is not associated with an improvement in OS.