This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gynaecological oncology, Subject name: Gynaecology & Obstetrics
All are indications for postoperative radiotherapy in a case of Carcinoma Endometrium Except 
Select and explain. 
A. Myometrial invasion >1/2 thickness, B. Positive lymph nodes, C. Endocervical involvement, D. Tumor positive for estrogen receptors
D: Tumor positive for estrogen receptors
Answer: D: Tumor positive for estrogen receptors 
Explanation: Pelvic postoperative radiotherapy (external) in a dose of 6000 cGy over a 6-week period is recommended in high-risk cases such as an undifferentiated tumor, myometrial infiltration, pelvic node involvement, and in serous, clear cell and adenosquamous carcinoma. The postoperative radiotherapy is required in Stages IA (Grade 3), IA2, IB and II. Whole-abdomen radiation is required when para-aoic lymph nodes are involved while protecting the liver and kidneys.The most impoant factors in considering the need for postsurgical radiotherapy are (1) histology; (2) grading as studied by biopsy and (3) depth of myometrial invasionas seen by ultrasound, MRI and at the time of surgery.Ref: Shaw&;s textbook of gynecology; 16th edition; Page no: 512