Definitive Radiotherapy in the Management of Non-Resectable or Residual Retroperitoneal Sarcomas: Institutional Cohort Analysis and Systematic Review

BACKGROUND: There is currently no consensus on optimal management of patients with primary or recurrent non-resectable/residual retroperitoneal sarcomas (RPS). The objective of this study was to document the outcomes of patients with primary or recurrent non-resectable/residual RPS treated in our center with definitive radiotherapy (RT) and to perform a systematic review on the topic. METHODS: A retrospective analysis of consecutive RPS patients treated in our center between 2000 and 2019 was performed. All consecutive patients who underwent definitive conformal RT with image guidance for primary or recurrent non-resectable or macroscopically residual RPS were included. Additionally, a systematic review compliant with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses was performed. RESULTS: The study enrolled 14 patients who met the aforementioned criteria. Data on clinicopathological characteristics, RT and response to treatment were assessed. RT allowed achieving prolonged local control of the disease, i.e. no local progression of the disease for more than 12 months after RT in 10 patients. Local control lasted more than 24 months in 6 cases, with minimal or no toxicity. A systemic review of 11 studies revealed concordance of our results with previous reports of primary or recurrent non-resectable/residual RPS. CONCLUSIONS: RT provided satisfactory local disease control with acceptable treatment tolerance in patients with primary or recurrent non-resectable/residual RPS and represents a valuable treatment modality in the selected group of patients. Additional RT modalities i.e. BT, particle therapy, MRI-guided RT, or GRID/Lattice RT may be introduced to improve local control and further minimize toxicity.