Multiparametric Quantitative MRI and Response to Neoadjuvant Radiotherapy for Soft-tissue Sarcoma

This trial is a prospective, monocentric, with minimal risks and constraints study, conducted in patients with Soft Tissue Sarcoma (STS) of the limbs and trunk with indication for neoadjuvant radiotherapy (RT).Patients will be treated by neoadjuvant RT and will have a pre-RT and a post-RT multiparametric quantitative Magnetic Resonance Imaging (MRI).A tumor resection will be performed 6 to 8 weeks post-RT and an anatomopathological observation of the surgical specimen will be performed.This study will allow to describe the initial remnographic characteristics and their evolution after neoadjuvant RT using quantitative multiparametric MRI (mpMRI).

INCLUSION CRITERIA :Patients 18 years of age or older;Documented histologic diagnosis of soft tissue sarcoma of the limbs or trunk;Validated indication for neoadjuvant radiotherapy, planned in the radiotherapy department of the Centre Léon Bérard;No contraindication to Magnetic Resonance Imaging,Signed informed consent;Affiliation with a social security system or beneficiary of such a system.EXCLUSION CRITERIA :Tumor considered as unresectable or patient considered as non-operable;Desmoid tumor or dermatofibrosarcoma protuberans due to intermediate malignancy;Rhabdomyosarcoma due to a different therapeutic management;Multi-metastatic disease;Pregnant or lactating woman,Patient under guardianship, curatorship or deprived of liberty.