iCREATE: imaging features of primary and metastatic alveolar soft part sarcoma from the EORTC CREATE study

BACKGROUND: Alveolar Soft Part Sarcoma (ASPS) is a rare, slow-growing, but highly vascular soft tissue sarcoma, characterised by a high rate of metastases at presentation. Although imaging features of the primary are well described, less detail is available on the imaging pattern of metastatic ASPS. The EORTC 90101 (CREATE) study assessed the efficacy of Crizotinib in patients with metastatic ASPS and presents a unique opportunity to describe the imaging phenotype of primary and metastatic ASPS, based on prospectively collected imaging. METHODS: A retrospective review of the staging CT scans of 32 patients with ASPS from the CREATE study was undertaken and the imaging features of primary and metastatic disease were assessed. RESULTS: Imaging of the primary tumour was available in 7/32 cases (28%). All primary tumours demonstrated marked vascularity with prominent feeding vessels (7/7, 100%). The most frequent sites of metastases included lung (30/32, 94%), nodal (7/32, 22%), bone (5/32, 16%) and muscle/subcutaneous (5/32, 16%). Features of hypervascularity were identified at all sites, more appreciable in the lungs, with feeding vessels frequently demonstrated in pulmonary metastases (21/32, 66%). CONCLUSION: Analysis of imaging from the CREATE cohort of patients with metastatic ASPS demonstrates that metastases from ASPS are predominantly hypervascular and demonstrate feeding vessels comparable to primary ASPS, suggesting potential sensitivity of this rare sarcoma for antivascular/antiangiogenic treatment approaches.