Assessment of the Long-term Efficacy of Moderately Hypofractionated Neoadjuvant Radiotherapy Soft Tissue Sarcoma in the Limbs or Trunk Wall

This trial aims to assess the long-term efficacy of moderately hypofractionated neoadjuvant radiotherapy for soft tissue sarcoma in the limbs or trunk wall. The primary outcome is local disease control, assessed by the cumulative incidence of progression/recurrence. After informed consent has been obtained and eligibility criteria have been checked, a baseline assessment will be performed followed by the experimental treatment: intensity-modulated radiotherapy with a moderately hypofractionated regimen consisting in 15 fractions of 2.7 Gy administered over 3 weeks. a follow-up assessment will be performed 3 to 4 weeks after the last radiotherapy session. Tumor resection will be performed 4 to 8 weeks after the radiotherapy. Patients will then be followed up until the end of the study; planned 5 years after the last inclusion. Radiotherapy will be evaluated in terms of safety and efficacy.

Inclusion Criteria: * Patient aged ≥ 18 years ; * Localised sarcoma of a limb, the root of a limb, or the trunk wall ; * Histologically confirmed diagnosis of soft tissue sarcoma regardless of the grade ; * Diagnosis biopsy performed at Centre Oscar Lambret, with specimen available for translational research ; * Indication of neoadjuvant radiotherapy according to the multidisciplinary consultation meeting ; * Tumor considered operable with a curative intent and conservative intent according to the multidisciplinary consultation meeting ; * Affiliation to the French National Social Security System ; * Informed and signed consent Exclusion Criteria: * Metastatic disease (including local lymph node diffusion) ; * Visceral or retroperitoneal sarcoma ; * Tumor considered inoperable even after radiotherapy, according to the multidisciplinary consultation meeting ; * Indication of neoadjuvant or adjuvant chemotherapy ; * Ewing tumor of soft tissue, desmoid tumor, embryonal or alveolar rhabdomyosarcoma ; * Pregnant or breastfeeding women ; * Patients under protective measures ; * Patient refusal.