Sentinel Lymph Node Sampling for Patients With Middle-high Risk Endometrial Cancer Confined to the Uterus

Inclusion Criteria: 1. Older than 18 years old; 2. Clinically diagnosed (by pre-surgical pathology and radiology) as primary endometrial cancer confined to uterus with middle-high risk factors: 1. disease limited to the uterus on image study (MRI, CT or ultrasound); 2. including all histological types of endometrial cancer (endometrioid, serous, clear cell, carcinosarcoma, and undifferentiated carcinoma); not including uterine sarcoma 3. excluding low-risk endometrial cancer (endometrioid G 1-2 with pre-surgical endometrial lesion≤2cm and myometrial invasion \<50%); 4. with one or more middle-high risk factors including: endometrioid endometrial cancer G3, myometrial invasion ≥50%, tumor size≥2cm, type II endometrial cancer, molecular classification of p53abn, LVSI; 5. diagnosis should be confirmed by at least two senior clinicians; 3. Be able to undergo staging surgery. Exclusion Criteria: 1. During pregnancy or perinatal period; 2. With synchronous malignancies or other malignancies than endometrial cancer in 3 years, except for non-melanoma skin cancer; 3. With history of important organs transplantation; 4. With immune diseases requiring taking immunosuppressants 5. With severe mental illness or brain function disorders 6. With history of drug abuse; 7. Allergic to contrast agent; 8. Still participating in other clinical trials; 9. Not willing to accept surgery or trial protocol; 10. Not eligible for surgery; 11. Had hysterectomy, chemotherapy, radiotherapy, or hormone therapy before the trail; 12. Had retroperitoneum lymph node dissection for other reasons.