• A written informed consent form must be signed before the implementation of any trial-related procedures.

• Female, aged 18 years or older and 80 years or younger.

• ECOG PS 0-1.

• Newly diagnosed with histologically or cytologically confirmed primary endometrioid adenocarcinoma, serous carcinoma, clear cell adenocarcinoma, undifferentiated carcinoma, mixed cell adenocarcinoma, mesonephric adenocarcinoma, mucinous carcinoma, intestinal-type mesonephric-like adenocarcinoma, and carcinosarcoma, meeting the clinical diagnostic criteria for endometrial cancer.

• Patients with locally recurrent or oligometastatic endometrial cancer after initial treatment. The number of recurrent and metastatic lesions is ≤5. Screening criteria for oligometastasis: lymph node metastases in the same region count as one metastatic lesion; liver metastases are limited to one; lung metastases are limited to three.

• At least one site suitable for radiotherapy (including the primary lesion), measurable, and meeting the RECIST v1.1 criteria for evaluable lesions.

• Tumor samples available for biomarker assessment.

• Expected survival time ≥6 months.

• Normal major organ function (within 7 days before enrollment), meeting the following criteria:

⁃ (1) Hematology standards (without blood transfusion or hematopoietic growth factor treatment within 14 days before enrollment):

• Hemoglobin (HB) ≥80 g/L;

• Absolute neutrophil count (ANC) ≥1.5×10\^9/L;

• Platelet count (PLT) ≥50×10\^9/L; (2) No functional or organic diseases, meeting the following criteria:

⁃ a) Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5×ULN, total serum bilirubin ≤1.5×ULN, alkaline phosphatase (ALP) ≤3×ULN, serum albumin ≥30 g/L; b) Serum creatinine (Cr) ≤1.5×ULN; if serum creatinine is \>1.5×ULN, creatinine clearance (CrCl) ≥50 mL/min (calculated using the Cockcroft-Gault formula); c) Prothrombin time (PT) prolongation ≤6 seconds, activated partial thromboplastin time (APTT) ≤1.5×ULN; d) Thyroid-stimulating hormone (TSH) ≤ULN (if abnormal, FT3 and FT4 levels should be considered; if FT3 and FT4 levels are normal, enrollment is allowed); f) Left ventricular ejection fraction (LVEF) \>50%. 11. Before starting the first treatment, all reversible toxic reactions from previous anti-tumor treatments must have resolved to ≤ grade 1 (based on CTCAE v5.0), excluding any grade of alopecia and pigmentation, ≤ grade 2 peripheral sensory neuropathy, and other abnormalities considered by the investigator and/or sponsor to pose a benefit-risk balance favoring the subject receiving the study treatment.

⁃ 12\. Non-surgically sterilized or childbearing potential female patients must use medically recognized contraception (e.g., intrauterine device, contraceptive pill, or condom) during the study treatment period and for 3 months after the end of the study treatment. Non-surgically sterilized childbearing potential female patients must have a negative serum or urine HCG test within 7 days before enrollment and must not be breastfeeding.