GnRHa + Letrozole in Obese Progestin-insensitive Endometrial Cancer Patients

Inclusion criteria

• Have a confirmed initial pathological diagnosis based upon hysteroscopy: histologically prove well-differentiated EEC G1 without myometrial invasion
• BMI≥30kg/m2
• No signs of suspicious extrauterine involvement on enhanced magnetic resonance imaging (MRI) or enhanced computed tomography (CT) or ultrasound
• Using progestin, any of the following therapy, as first-line treatment:
• Megestrol acetate ≥ 160 mg qd using, combined with Levonorgestrel Lntrauterine System (LNG-IUS) inserted or not
• Medroxyprogesterone acetate ≥ 250 mg qd using, combined with LNG-IUS inserted or not
• LNG-IUS inserted
• Progestin-insensitive:
• remained with stable disease after 7 months of progestin use
• did not achieve CR after 10 months of progestin use
• Have a desire for remaining reproductive function or uterus
• Good compliance with adjunctive treatment and follow-up

Exclusion criteria

• Combined with severe medical disease or severely impaired liver and kidney function
• Pathologically confirmed as endometrial cancer with suspicious myometrial invasion or extrauterine metastasis
• Patients with other types of endometrial cancer or other malignant tumors of the reproductive system
• Patients with breast cancer or other hormone- dependent tumors or diseases that cannot be used with GnRHa or Letrozole
• Strong request for uterine removal or other conservative treatment
• Known or suspected pregnancy
• Acute severe disease such as stroke or heart infarction or a history of thrombosis disease
• Smoker(\>15 cigarettes a day)