Value of LNG-IUS as Fertility-preserving Treatment of EAH and EC

For Patients With Endometrial Cancer： Inclusion Criteria: * ≤40 years of age: * Having a strong desire for fertility preservation; * Histological diagnosis is confirmed as well-differentiated (grade 1) endometrioid adenocarcinoma by the designated gynecological pathologists, and the progesterone receptors (PgRs) is positive in immunohistochemistry; * Disease limited to the endometrium (stage 1A) on MRI; * Serum CA125/199 level is within normal limit (Laparoscopic exploration to rule out ovarian tumor or another metastasis if necessary); * Patients should have undergone counseling to learn fertility-preserving treatment is not standard of care for the treatment of EC, volunteered to participate in this study, signed the informed consent form, and agreed to participated in clinical follow-up. Exclusion Criteria: * Patients have allergies or contraindications (except for thromboembolic disease, liver dysfunction, hypertension, and diabetes) for the involved drugs; * Patients have lynch syndrome (LS); * Patients have contraindications for pregnancy; * Patients have serious underlying disease, malignancies at other site(s), acute liver or kidney disease, acute liver or kidney diseases, acute or subacute genital tract infections and congenital or acquired abnormal uterine development (that may make intrauterine device placement impossible); * Patients refuse to participate in clinical follow-up or sign the informed consent form. For Patients With Endometrial atypical hyperplasia： Inclusion Criteria: * ≤ 40 years of age * Having a strong desire for fertility preservation * Histological diagnosis is confirmed as atypical endometrial hyperplasia (EAH) by the designated gynecological pathologists * Having volunteered to participate in this study, signed the informed consent form, and agreed to participate in clinical follow-up Exclusion Criteria: * Patients have allergies or contraindications (except for thromboembolic disease, liver dysfunction, hypertension, and diabetes) for the involved drugs * Patients have contraindications for pregnancy * Patients have serious underlying disease, malignancies at other site(s), acute liver or kidney disease, acute or subacute genital tract infections, and congenital or acquired abnormal uterine development (that may make intrauterine device placement impossible) * Patients refuse to participate in clinical follow-up or sign the informed consent form.