The importance of the margin of resection and external radiation in non-lipomatous retroperitoneal sarcoma

BACKGROUND: Prior studies evaluating the impact of adjuvant or neoadjuvant radiation on clinical outcomes of patients with non-lipomatous retroperitoneal sarcoma have been underpowered. METHODS: We queried the National Cancer Database to identify patients undergoing surgical resection of retroperitoneal sarcoma with non-lipomatous histology from 2004 to 2016. Multivariable logistic regression and Cox proportional hazards modelling with patients stratified by tumor size were used to identify factors associated with overall survival. RESULTS: 3,394 patients met inclusion criteria. 592 had small (10 cm) tumors. Use of either neoadjuvant or adjuvant radiotherapy was associated with improved survival for patients with intermediate (neoadjuvant HR 0.67, CI [0.46, 0.98]; adjuvant HR 0.61, CI [0.50, 0.76]) and large (neoadjuvant HR 0.50, CI [0.37, 0.68]; adjuvant HR 0.56, CI [0.47, 0.69]) tumors, while adjuvant radiation therapy was associated with a survival benefit for small-sized tumors (HR 0.67, CI [0.46, 0.99]). CONCLUSIONS: Radiation therapy is associated with an overall survival benefit in patients presenting undergoing resection of non-lipomatous retroperitoneal sarcoma.