Cryoablation Versus Medical Therapy in Desmoid Tumors Progressing After Watchful Waiting

Inclusion Criteria: * Subject (male or female) with extra-peritoneal desmoid tumor (confirmed by prior biopsy by an experienced pathologist within the RRePS network) * 13 years of age or older * Measurable viable tumor (according to the mRECIST criteria using MRI. The baseline MRI imaging is mandatory in the 2 months prior to treatment initiation (D0). * Progressive disease (according to the mRECIST criteria) after the watchful waiting period or significant increase in symptoms requiring an active therapy, as advised in a multidisciplinary sarcoma tumor board * Tumor deemed accessible for cryoablation procedure by the operator in a type I center. (In pediatric cases, a careful site tumor analysis will be performed with interventional radiologist to ensure for limited consequence of cryoablation in pediatric patients especially regarding growth plates). * 100 % of destruction of the tumor achievable in one procedure of cryoablation with 1cm security margin according to assessment by referral center (type 1) for cryoablation * ECOG performance status 0-2 at inclusion visit * Biological and hematological parameters (neutrophils ≥ 1,5.109/L ; platelet count ≥ 100.109/L ; no significant hemostatic abnormalities) in the 4 weeks prior to treatment initiation (D0) * Subject able to understand the objectives and risks of the research and to give dated and signed informed consent. For minors, the consent of the 2 parents must be obtained. * Subject affiliated to a social health insura…