Intensity-Modulated Radiation Therapy to the Pelvis With or Without Chemotherapy in Treating Patients With Endometrial Cancer or Cervical Cancer That Has Been Removed By Surgery

DISEASE CHARACTERISTICS:

• Must have undergone a hysterectomy (total abdominal, vaginal, radical, or laparoscopic-assisted vaginal) within 7 weeks prior to study entry
• Patients with endometrial cancer must have also undergone a bilateral salpingo-oophorectomy
• 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)

PATIENT CHARACTERISTICS:

• Zubrod performance status 0-2
• WBC (white blood cell count) ≥ 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 (aspartate aminotransferase) ≤ 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