Intrauterine Injection of Type III Collage in FST of EC/AEH

Inclusion Criteria: 1. Pathological diagnosis of endometrioid adenocarcinoma (G1 or G2) or atypical endometrial hyperplasia. 2. For patients with endometrial cancer, magnetic resonance imaging (MRI) or ultrasound must confirm that the lesion is confined to the endometrium or invades less than 1/2 of the myometrium (i.e., FIGO 2009 Stage IA). 3. Age ≤ 45 years. 4. Desire to preserve fertility and signed informed consent. 5. No serious medical comorbidities (e.g., severe liver or renal dysfunction). 6. No contraindications to progestin therapy or pregnancy. 7. No evidence of distant metastasis on imaging. Exclusion Criteria: 1. Tumor invasion \> 1/2 of the myometrium, or FIGO (2009) Stage IB and above. 2. Tumor differentiation grade G3 or non-endometrioid adenocarcinoma. 3. Coexistence of other malignant tumors. 4. Contraindications to conservative treatment or use of the study drugs. 5. Known allergy to recombinant protein components. 6. Acute genital tract inflammation or untreated abnormal vaginal discharge within 2 weeks prior to enrollment. 7. Previous treatment with high-potency progestin for more than 1 month.