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.