Interest of Peri Operative CHemotherapy In Patients With CINSARC High-risk Localized Soft Tissue Sarcoma

Phase III, multicenter, randomized open-label and comparative study designed to demonstrate whether adding 4 cycles of peri-operative doxorubicin-based chemotherapy improves metastasis-free survival as compared with standard management in patients with resectable STS, considered as high-risk according to CINSARC (Complexity Index in SARComas) signature. After signed informed consent, patients considered as eligible to CHIC-STS study by the investigator will be enrolled in the study and a molecular screening will be performed (600 patients will be screened). Patients considered as low-risk according to CINSARC signature will be treated at the discretion of the clinicians (prospective cohort). Patients considered as high-risk according to CINSARC signature will be randomized in the open-label multicenter phase III trial and assigned in one of the two following treatments arms: * Arm A (control arm): Standard of care (surgical excision +/- external radiotherapy). * Arm B (experimental arm): Standard of care + 4 cycles of intravenous chemotherapy during 12 weeks. A total of 250 patients will have to be randomized with 125 patients in each arm.