Evaluation of Clinical Impact of Interruption VS Maintenance of AI in Patients With Locally Advanced/ Metastatic Low Grade Endometrial Stromal Sarcoma (LGESS)

Inclusion Criteria:

* Age≥18 years;
* Histological confirmation of low grade ESS;
* Locally advanced or metastatic disease at diagnosis or patient experiencing a tumor effraction during hysterectomy;
* Treatment with aromatase inhibitors (Anastrozole or Exemestane or Letrozole ) initiated either: for at least 24 months (in patients with no residual disease or non-measurable disease at the last AI initiation) OR for at least 36 months (in patients with measurable disease at the last AI initiation);
* Disease must be controlled at the time of the randomisation (objective response or stable disease) by the aromatase inhibitor initiated either for at least 24 or 36 months
* Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) ≤ 2
* Covered by a medical insurance;
* Signed informed consent prior to any study-specific procedure.

Exclusion Criteria:

* Pregnant or breastfeeding woman;
* Patient concurrently using other approved or investigational antineoplastic agents;
* Major concurrent disease affecting cardiovascular system, liver, kidneys, hematopoietic system or else considered as clinically important by the investigator and that could be incompatible with patient's participation in this trial or would likely interfere with study procedures or results;
* Prior history of malignancies other than study disease (except for basal cell or squamous cell carcinoma of the skin or carcinoma in situ of the cervix) unless the patient has been free of the disease for at least 3 years;
* Patients using prohibited concomitant and/or concurrent medications
* Contra-indication according to SmPCs.
* Patient requiring tutorship or curatorship.