Stereotactic Ablative Radiation (SABR/SBRT) will be prescribed to a dose of 30 Gy in 5 fractions, once weekly to the pelvis in post operative patients with endometrial cancer.

Inclusion Criteria:

• Patient with histologically confirmed endometrial adenocarcinoma
• Patient is a candidate for adjuvant pelvic radiation (+/- vault brachytherapy), meeting one of the following conditions: High grade histology OR Outer-half myometrial invasion with any risk factors OR FIGO stage II - IIIC1.
• Age ≥18 years.
• Patients who are to receive adjuvant systemic therapy in addition to pelvic radiotherapy will be eligible provided that there is at minimum a 3-week interval between any radiation treatment and chemotherapy treatments.

Exclusion Criteria:

• Patient has had prior pelvic radiotherapy.
• Patient has Type II endometrial cancer histology (ie. Serous, clear cell or carcinosarcoma).
• Patient has a contraindication to pelvic radiotherapy, such as but not limited to a connective tissue disease or inflammatory bowel disease.
• Patient has a contraindication to CT contrast.
• Patient has a hip prosthesis.