Abstract PO-027: Associations of radiomics features with tumor necrosis following chemotherapy and/or radiation therapy in patients with extremity soft tissue sarcoma
Authors: Grosso James , Subhawong Ty , Stoyanova Radka , Yechieli Raphael , Seldon Crystal , Prosperi Blase 
Published: March 2021

Abstract
Introductory sentence: The purpose of this study is to identify MRI radiomic features of sarcomas pre and post treatment with radiation and/or chemotherapy that correlate with the level of necrosis demonstrated on pathology report upon tumor excision. Experimental procedures: Patients with soft tissue upper and lower extremity sarcomas and available pre- and post-treatment MRI exams were included in the study. For the purposes of this study we utilized T2 fat saturated imaging sequences. We employed MINT Lesion radiomics software for extraction of quantitative imaging data. The lesions Regions of Interest (ROIs) were manually contoured MRI scans before and after chemotherapy and/or radiation therapy. Following treatment, patients had their tumors excised with corresponding tumor necrosis data recorded. Using Pearson correlation statistics, the percent necrosis was compared to radiomic changes (delta-radiomics). Summary of data: Fifty-two patients, treated between 2012 and 2020 were included in the study. The clinical characteristics were: male – (56%) and female- (44%); type of sarcomas ranged from Liposarcoma, Leiomyosarcoma, Myxofibrosarcoma, among others; Grade 2-3; Treatment with radiation and/or chemotherapy of different doses and regimens. MRIs were acquired within 3 months before initiation of treatment and within 2 months after treatment. Surgery was subsequently performed within 2 months of last MRI scan. The average necrosis on final pathology was 68% +/- 33% std. Total of 41 radiomic features were extracted from the ROIs. Five of the delta-radiomics parameters were significantly correlated with necrosis (p-value &lt; 0.05) and sixteen were marginally associated (p-value &lt; 0.1). The significantly correlated radiomic features includes first and second order values representing the distribution of voxel intensities within the segmented image regions and the statistical inter-relationships between neighboring voxels, respectively. Conclusions: In this pilot study we identified delta-radiomics features, related to first order radiomic data, or increased voxel intensity, and second order radiomics, or increased vowel heterogeneity, associated with the level of necrosis within sarcomas post radiation and/or chemotherapy. This data will be followed up with larger patient samples and including additional sequences for delta-radiomics analysis, such as Diffusion Weighted Imaging and Dynamic Enhanced Contrast to develop prediction models for necrosis levels.
Citation Format: James Grosso, Ty Subhawong, Radka Stoyanova, Raphael Yechieli, Crystal Seldon, Blase Prosperi. Associations of radiomics features with tumor necrosis following chemotherapy and/or radiation therapy in patients with extremity soft tissue sarcoma [abstract]. In: Proceedings of the AACR Virtual Special Conference on Artificial Intelligence, Diagnosis, and Imaging; 2021 Jan 13-14. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(5_Suppl):Abstract nr PO-027.