Interest of Post-operative Chemotherapy in Patients With Localised Uterine Leiomyosarcoma Suspected of Having a High Risk of Recurrence Based on a Biological Test Performed on the Tumour

Addition of postoperative chemotherapy to prevent or delay recurrence in patients newly diagnosed with localized uterine leiomyosarcoma and who have undergone complete tumor surgery.

This is a biological driven study comprising: * a multicenter, randomized and comparative phase II trial designed to demonstrate whether adding 4 cycles of post-operative chemotherapy improves relapse-free survival as compared with follow-up (standard management) in patients with resected FIGO stage I uterine leiomyosarcoma, considered at high-risk according to CINSARC NanoCind® signature. * a prospective cohort for patients with resected FIGO stage I uterine leiomyosarcoma, considered at low-risk according to CINSARC NanoCind® signature. HIGH-RISK (HR) CINSARC patients will be randomized post-operatively between the two arms of treatment, i.e. standard treatment (active post-surgical surveillance) or chemotherapy, with a 1:1 randomization on one factor: morcellation versus no morcellation of uterine tumor. LOW-RISK (LR) CINSARC patients' data will be prospectively collected