Inclusion Criteria

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