RATIONALE: External-beam radiation therapy uses high-energy x-rays to kill tumor cells. Implant radiation therapy uses radioactive material placed directly into or near a tumor to kill tumor cells. Giving external-beam radiation therapy or implant radiation therapy after surgery may kill any tumor cells that remain after surgery. Sometimes, after surgery, the tumor may not need more treatment until it progresses. In this case, observation may be sufficient. It is not yet known whether radiation therapy is more effective than observation when given after surgery in treating stage I endometrial cancer.

PURPOSE: This randomized phase III trial is studying external-beam radiation therapy or implant radiation therapy to see how well they work compared with observation in treating patients who have undergone surgery for stage I endometrial cancer.

OBJECTIVES:

• Compare the rate of 5-year locoregional relapse in patients undergoing external-beam radiotherapy or vaginal brachytherapy vs observation only after surgery for stage I endometrial cancer.
• Compare 5-year rate of distant metastases in these patients.
• Determine overall survival rate in these patients.
• Determine prognostic factors for relapse and morbidity.

OUTLINE: This is a randomized, multicenter study. Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients undergo either vaginal brachytherapy or external-beam radiotherapy.
• Arm II: Patients are observed and undergo no further treatment. After completion of study treatment, patients are followed for approximately 83 days.

PROJECTED ACCRUAL: A total of 400 patients will be accrued for this study.

INCLUSION CRITERIA:

• Diagnosis of FIGO 1988 stage I-IIA endometrial cancer, meeting 1 of the following criteria:

  • Age ≥60, stage IC grade 1 or 2 with deep (≥ 50%) myometrial invasion
  • Age ≥60, stage IB grade 2 or 3 (with < 50% myometrial invasion)
  • Stage IIA, any age

• No grade 3 endometrial carcinoma with deep myometrial invasion

• Total abdominal hysterectomy and bilateral salpingo-oophorectomy required prior to randomisation

• WHO performance status 0-2

EXCLUSION CRITERIA:

• Serous or clear cell histology or uterine sarcoma
• staging lymphadenectomy
• interval between surgery and radiotherapy > 8 weeks
• history of previous malignant disease (except basal cell carcinoma of skin)
• previous radiotherapy, hormonal therapy or chemotherapy
• diagnosis of Chrohn's disease or ulcerative colitis

After submission of a research plan and approval by the TMG data will be shared