Adjuvant radiotherapy (RT) plays an important role in reducing the risks of local recurrence after surgery in uterine cancers. Standard adjuvant pelvic radiation treatment targets the pelvic lymph nodes, the post-operative bed, and the upper vagina and is typically treated with intensity modulated radiation therapy (IMRT) which has been shown to improve patient reported gastrointestinal (GI) and genitourinary (GU) toxicities. Although pelvic radiation has been shown to be effective at decreasing locoregional recurrences, patient quality of life and experience can be significantly impacted as pelvic RT comprises of daily radiation for 25 daily treatments, which can be a substantial burden on patients with this disease. Hypofractionated radiotherapy to a dose of 30 Gy in 5 fractions (6 Gy given every other day) for adjuvant radiation treatment in uterine cancer is hypothesized to result in similar rates of acute gastrointestinal toxicities as conventional fractionated radiation.

Inclusion Criteria:

1. Patient with histologically confirmed endometrial adenocarcinoma, serous or clear cell carcinoma.

2. Patient is a candidate for adjuvant pelvic radiation for uterine cancer (+/- vault brachytherapy), meeting one of the following conditions:

   High grade histology (including serous and clear cell) OR Outer-half myometrial invasion and International Federation of Gynecology and Obstetrics (FIGO) grade 1-2 OR FIGO stage II - III.

3. Patients who are to receive adjuvant systemic therapy sequentially in addition to pelvic radiotherapy will be eligible.

4. Age ≥18 years.

5. Patient is willing and able to give informed consent to participate in this clinical trial.

Exclusion Criteria:

1. Patient has had prior pelvic radiotherapy.
2. Patient has a contraindication to pelvic radiotherapy, such as but not limited to a connective tissue disease or inflammatory bowel disease.
3. Patient planned for concurrent chemoradiation therapy.