DISEASE CHARACTERISTICS:

• Histologically confirmed diagnosis of 1 of the following:

  • Endometrial cancer meeting 1 of the following criteria:

    • Stage IB grade 3, IC grade 1-3, IIA, or IIB disease requiring postoperative pelvic radiotherapy
    • Unstaged (no lymph node dissection or sampling) stage IB grade 2 disease

    • Stage IIIC with all of the following:

      • Pelvic lymph node positive only
      • Para-aortic nodes sampled negative
      • Not receiving chemotherapy

  • Cervical cancer meeting 1 of the following criteria:

    • Post-radical hysterectomy and requires postoperative pelvic radiotherapy due to any of the following:

      • Positive pelvic nodes (negative para-aortic nodes)
      • Microscopic parametrial involvement and negative margins

      • Disease qualified by Sedlis criteria must have 2 of the following risk factors:

        • 1/3 or more stromal invasion
        • Lymph-vascular space invasion
        • Large clinical tumor diameter (≥ 4 cm)
    • Post-simple hysterectomy with negative margins and negative nodes by CT scan, MRI, or positron emission tomography-CT scan
• No requirement for extended-field radiotherapy beyond the pelvis
• No histologically confirmed papillary serous, clear cell, or neuroendocrine (either large or small cell) disease, endometrial stromal sarcoma, leiomyosarcoma, or malignant müllerian mixed tumor
• No evidence of metastatic disease outside of the pelvis
• No microscopic involvement of the resection margin (< 3 mm)

• Must have undergone a hysterectomy (total abdominal, vaginal, radical, or laparoscopic-assisted vaginal) in the past 7 weeks

  • Patients with endometrial cancer must have also undergone a bilateral salpingo-oophorectomy

PATIENT CHARACTERISTICS:

• Zubrod performance status 0-2
• WBC ≥ 4,000/mm³ (cervical cancer patients only)
• Absolute neutrophil count ≥ 1,800/mm³ (cervical cancer patients only)
• Platelet count ≥ 100,000/mm³ (cervical cancer patients only)
• Hemoglobin ≥ 8.0 g/dL (transfusion allowed)
• Serum creatinine ≤ 2.0 mg/dL (cervical cancer patients only)
• Creatinine clearance ≥ 50 mL/min (cervical cancer patients only)
• AST ≤ 2 times upper limit of normal
• Bilirubin ≤ 2 times upper limit of normal

• Patients must not exceed the weight and size limits of the treatment table or CT scanner

  • No mental status changes or bladder control problems that would preclude study compliance with bladder-filling instructions
• No active inflammatory bowel disease

• No severe, active, concurrent illness, defined as any of the following:

  • Unstable angina and/or congestive heart failure requiring hospitalization within the past 6 months
  • Transmural myocardial infarction within the past 6 months
  • Acute bacterial or fungal infection requiring IV antibiotics
  • Chronic obstructive pulmonary disease exacerbation or other respiratory illness requiring hospitalization or precluding study therapy
  • Hepatic insufficiency resulting in clinical jaundice and/or coagulation defects
  • AIDS
• No history of allergy to cisplatin (cervical cancer patients)
• No prior invasive malignancy (except nonmelanoma skin cancer) unless disease-free for ≥ 3 years

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• No prior radiotherapy to the pelvis that would result in overlap of radiotherapy fields
• No prior platinum-based chemotherapy (cervical cancer patients)
• No concurrent prophylactic growth factors (e.g., filgrastim [G-CSF], sargramostim [GM-CSF], or pegfilgrastim)
• No concurrent prophylactic thrombopoietic agents
• No concurrent amifostine or other protective agents