The ASTRO expert panel consisted of 17 leading gynecologists who collated and studied large data from 330 studies published from 1980 to 2011 in databases such as MEDLINE, EMBASE and Cochrane. The guideline’s data source population was defined as women of all races with endometrial cancer of any histologic type or grade, ages 18 years and older, stage I through IV. Patients included in the study were those who had no adjuvant therapy after hysterectomy or had pelvic and/or vaginal brachytherapy or no systemic chemotherapy. The panel asked five key questions about adjuvant radiation therapy and gave a series of recommendations to explain the above key questions. In which cases is complementary therapy required after hysterectomy? It is reasonable not to choose adjuvant radiation therapy for hysterectomy specimens without residual disease, even if the biopsy is positive or for grade 1 or 2 cancers without invasion or <50% myometrial infiltration, especially when no other high-risk features are present. patients with grade 3 cancers without myometrial infiltration or grade 1 or 2 cancers with <50% myometrial infiltration and the presence of high-risk factors such as age >60 years and/or lymphatic gap invasion, then it is reasonable to receive or not receive vaginal dissection brachytherapy. What are the circumstances that warrant vaginal dissection radiotherapy after hysterectomy? Evidence suggests that brachytherapy is similar to pelvic radiotherapy in preventing recurrence of the vaginal dissection in patients with grade 1 or 2 cancer with ≥50% myometrial infiltration or grade 3 cancer with <50% myometrial infiltration. For patients with these risk factors, especially those evaluated by comprehensive lymph node assessment, brachytherapy to the vaginal dissection is superior to pelvic radiotherapy. In what cases is external radiation radiotherapy required after hysterectomy? Patients with grade 3 early endometrial cancer with ≥50% myometrial infiltration or cervical stromal infiltration are considered to be at reduced risk of pelvic recurrence with pelvic radiotherapy. Patients with grade 1 or 2 cancer and ≥50% myxoid infiltration of the tumor may also receive pelvic radiotherapy to reduce the risk of pelvic recurrence if other risk factors such as age >60 years and/or vascular infiltration are present. The best evidence suggests that treatment including external radiation radiotherapy and adjuvant chemotherapy should be used for patients with positive lymph nodes or involvement of the uterine plasma membrane, ovaries and fallopian tubes, vagina, bladder or rectum. Chemotherapy or radiation monotherapy may be used for certain patients with pathologic risk factors for pelvic recurrence. Is additional brachytherapy necessary after external irradiation? There is a lack of data to validate the effectiveness of using brachytherapy after pelvic radiotherapy, and the sample size enrolled in the retrospective study was too small to give conclusive evidence regarding benefit. Patients receiving external pelvic radiation radiotherapy may not require concurrent vaginal brachytherapy unless the patient has risk factors for vaginal recurrence. How is radiotherapy and chemotherapy integrated in the comprehensive management of endometrial cancer? The expert committee concluded that the best evidence suggests that concurrent radiotherapy-chemotherapy sequential adjuvant chemotherapy is recommended for patients with positive lymph nodes or involvement of the uterine plasma membrane, ovaries and fallopian tubes, vagina, bladder or rectum. Alternative procedural treatment strategies may also be external radiation radiotherapy plus chemotherapy. Chemotherapy or radiation monotherapy may be used for certain patients with risk factors for pelvic recurrence pathology.