IntroductionFor retroperitoneal sarcomas (RPS), aggressive surgical resection offers the only chance for a cure; however, 5-year survival remains below 65%. Therefore, there is a critical need to identify drivers of poor clinical outcomes. Materials and MethodsTo identify biomarkers of tumors likely to recur following curative intent resection, we performed genomic and transcriptomic sequencing for 47 and 34 patients, respectively, with non-metastatic RPS at a single, high-volume sarcoma center. ResultsAt the DNA level, alterations in TERT were associated with poor disease-free survival (DFS) and overall survival (OS). Increased RNA expression of gene sets related to growth signaling and DNA repair were associated with poor DFS and OS. Infiltration of CD8+ T-Cells and activated dendritic cells were associated with poor DFS and OS. ConclusionThese findings may help to better identify and treat non-metastatic, high-risk RPS.