This phase I/II feasibility study of hypo-fractionated, image-guided Volumetric Modulated Arc Therapy (VMAT) Stereotactic Body Radiotherapy (SBRT) to the vaginal cuff in intermedium and high risk endometrial cancer. The primary endpoints are SBRT feasibility and dosimetrical reproducibility to HDR brachytherapy, inter/intra-fractional target motion assessment and toxicity rates. Secondary endpoints are quality of life measures, local control, disease free survival and overall survival.

This phase I/II feasibility study of hypo-fractionated, image-guided Volumetric Modulated Arc Therapy (VMAT) Stereotactic Body Radiotherapy (SBRT) to the vaginal cuff aims to reproduce adjuvant High Dose Rate (HDR) brachytherapy dose distributions in patients operated for intermediate and high risk endometrial carcinoma. The study will employ devices to accurately reproduce pelvic anatomy and mitigate target motion and will make use of real-time on-line tracking. Eligible patients will receive three SBRT sessions to a prescription dose of 7 Gy to the vaginal cuff (with 4 to 7 days interval). SBRT will start within 4 to 8 weeks post-hysterectomy. The study will enroll a total of 30 patients. After treatment, patients will be followed-up at 3 months (+/- 6 weeks), at 6 (+/- 6 weeks) and every 6 months (+/- 6 weeks) thereafter for a total of 2 years. The duration of accrual in the study will be up to 3 years. Toxicity and outcome will be compared to published data on the standard modality of care (HDR brachytherapy). Patients' quality of life measures will be collected with validated questionnaires at the baseline and during follow up. Recurrence rates and survival data will be reported.

Inclusion Criteria:

• Pathology proven adenocarcinoma of the endometrium
• National Comprehensive Cancer Network (NCCN) intermediate and high risk
• Unstaged patients with < 50% myometrium invasion;
• Age ≥ 18;
• World health organization - Eastern Cooperative Oncology Group (WHO-ECOG) performance status 0-2 or Karnofsky performance status (KPS) ≥ 70;
• Hemoglobin ≥ 8.0 g/dl; white blood cells count (WBC) ≥ 1,500/mm3 ; Platelets ≥ 40,000 cells/mm3 .
• Signed informed consent

Exclusion Criteria:

• Evidence of post-surgical macroscopic residual disease;
• Patients with anatomical incompatibility with online tracking device;
• Psychiatric conditions;
• Prior invasive malignancy (except non-melanomatous skin cancer) unless disease free for a minimum of 3 years;
• Prior radiation therapy to the pelvis that would result in overlap of radiation therapy fields;
• Severe active co-morbidities.