Soft tissue sarcomas are a heterogeneous group of malignant tumors. Undifferentiated pleomorphic sarcomas (UPS) are the largest subgroup of soft tissue sarcomas, accounting for approximately 20% of all cases. They can occur anywhere in the body and at any age; although pleomorphic tumors are more common in older patients, round-cell tumors occur more frequently in younger individuals. Post-therapeutically, these tumors may demonstrate hemosiderin deposition, granulation tissue formation, fibrosis, and calcification. After undergoing chemotherapy or radiation therapy, assessing the response of soft-tissue tumors (STS) can be...

This retrospective study included 26 extremity non-myxoid UPS patients with imaging and resection from February 2021-October 2022. Volumetric tumor segmentation from DWI/ADC, CE-SWI, and PWI/DCE were obtained at Baseline (BL), Post-Chemotherapy (PC), and Post-Radiation (PRT)/Pre-Surgical MRIs using the MIM commercial software. A total of 107 radiomic features, including first- and high-order statistics, were extraxcted from the ADC and CE-SWI images using our in-house developed software (CARPI-AF: Cancer Radiomic and Perfusion Imaging Automated Framework). In addition, 7 semi-quantiative kinetic parameters were computed from the PWI/DCE images...

Traditional Response Criteria in UPS [Fig 1]Figure 1 shows that all good responders and partial/non-responders post-radiation tumors are in the range of stable disease by RECIST, WHO and Volume. RECIST, WHO, and Volumetric criteria cannot separate good responders from partial/non-responders. Pseudo progression at PC happens on RECIST on all cases, on WHO in good responders and in Volumetric in all cases, and it is most significant at the end of systemic therapy. The highest degree of pseudo progression is seen at PC in good responders,...

RECIST and WHO criteria often cannot separate good from partial/non-responders. Good responders displayed post-chemotherapy volumetric pseudo-progression and a significant decrease in SWI mean. At post-radiation/pre-surgical they demonstrated >40% ADC increase, CE-SWI "Complete Ring," PWI/DCE Type II TIC and "capsular-like" patterns. Suboptimal responders showed PRT incomplete CE-SWI ring, TIC III/IV/V, and unipolar or bipolar enhancement. Multiparametric MRI is a valuable tool for UPS treatment assessment.

R. F. Valenzuela: Nothing to disclose E. Duran-Sierra: Nothing to disclose M. Canjirathinkal: Nothing to disclose C. M. Costelloe: Nothing to disclose H. Idrees: Nothing to disclose J. E. Madewell: Nothing to disclose W. Murphy: Nothing to disclose B. Amini: Nothing to disclose

WHO classification of tumours of soft tissue and bone – 4th edition / edited by Christopher D.M. Fletcher et al. ISBN 978-92-832-4491-2 pag 236-238. Soldatos T, Ahlawat S, Montgomery E, Chalian M, Jacobs MA, Fayad LM. Multiparametric Assessment of Treatment Response in High-Grade Soft-Tissue Sarcomas with Anatomic and Functional MR Imaging Sequences. Radiology. 2016 Mar;278(3):831-40. doi: 10.1148/radiol.2015142463. Epub 2015 Sep 21. PMID: 26390048; PMCID: PMC4770945. Subhawong TK, Wilky BA. Value added: functional MR imaging in management of bone and soft tissue sarcomas. Curr Opin Oncol....