Hypofractionated External Beam Radiotherapy With Adaptive Planning for Endometrial and Cervical Cancers

After surgery to remove the main endometrial and/or cervical tumor, most women receive radiation therapy. This study uses hypo-fractionated radiation therapy, which is a type of radiation therapy in which the total prescribed dose of radiation is delivered in fewer but larger doses than conventional or standard radiotherapy. This research study aims to determine if hypo-fractionated radiation therapy given after surgery can improve treatment tolerability (i.e., fewer treatments) with comparable side effects. Participants will be in the study for about 5 years: Radiation therapy: * 5 daily treatment sessions of MRI or CT-Guided Stereotactic Body Radiation Therapy (SBRT). * Each treatment session will occur on a weekday (typically consecutive weekdays) and will last approximately an hour. Treatment Follow-Up: * Check-up Appointment and answer questions at 3 months post RT * Check-up Appointments with physical exam every 6 months (+/- 4 weeks) for up to 5 years.

Inclusion Criteria: * Histologically confirmed endometrial or cervical cancer * Surgical resection of the primary tumor * International Federation of Gynecology and Obstetrics (FIGO) Stage IA-IVB endometrial cancer OR FIGO Stage IA-IIA cervical cancer that meets indications for receiving adjuvant pelvic radiotherapy alone as standard of care * Age ≥ 18 years old * Karnofsky performance status (KPS) ≥ 60 or Eastern Cooperative Oncology Group (ECOG) 0-2 Exclusion Criteria: * Must not meet indications for receiving concurrent chemotherapy as standard of care * Active treatment of a separate malignancy * History of prior irradiation to the area to be treated