Standard Versus Intensity-Modulated Pelvic Radiation Therapy in Treating Patients With Endometrial or Cervical Cancer

OBJECTIVES: Primary * To determine if pelvic intensity-modulated radiation therapy (IMRT) reduces acute gastrointestinal toxicity in the 5th week (after 23-25 fractions) of pelvic radiation as measured with the expanded prostate cancer index composite (EPIC) instrument. Secondary * To determine if grade 2+ gastrointestinal toxicity (Common Terminology Criteria for Adverse Events version 4.0 \[CTCAE v. 4.0\]) is reduced with IMRT compared to conventional whole-pelvis radiation therapy (WPRT). * To determine if grade 2+ hematologic toxicity (CTCAE v. 4.0) is reduced with IMRT compared to conventional WPRT. * To determine if urinary toxicity is reduced with IMRT using the EPIC urinary domain. * To validate EPIC bowel and urinary domains in women undergoing either IMRT pelvic radiation treatment or four-field pelvic radiation treatment for endometrial or cervical cancer. * To assess the impact of pelvic IMRT on quality of life using the Functional Assessment of Cancer Therapy-General (FACT-G) with cervix subscale. * To determine if there is any difference in local-regional control, disease-free survival, and overall survival between patients treated with IMRT as compared to conventional WPRT. * To perform a health-utilities analysis to measure the financial impact of pelvic IMRT via the EQ-5D instrument. * To identify molecular predictors of radiation toxicity and novel circulating cancer biomarkers. OUTLINE: This is a multicenter study. Patients are stratified according to type of cancer (endometrial vs cervical), chemotherapy (none vs 5 courses of weekly cisplatin at 40 mg/m²), and radiation dose (45 Gy vs 50.4 Gy). Patients are randomized to 1 of 2 treatment arms. * Arm I: Patients undergo standard (3-dimensional) radiation therapy 5 days a week for up to 5-6 weeks. * Arm II: Patients undergo intensity-modulated radiation therapy (IMRT) 5 days a week for up to 5-6 weeks. Some patients receive cisplatin IV over 1 hour on day 1. Treatment continues weekly for 5 weeks, concurrently with radiation therapy, in the absence of unacceptable toxicity or disease progression. Tissue and blood samples may be collected for biomarker and correlative analysis. Quality of life may be assessed by questionnaires (including the Expanded Prostate Cancer Index Composite \[EPIC\], the Functional Assessment of Cancer Therapy-General \[FACT-G, Version 4\], the EQ-5D, and the Common Toxicity Criteria Adverse Events - Patient-Reported Outcome \[PRO-CTCAE\]) instruments at baseline and periodically during and after study therapy. After completion of study therapy, patients are followed every 6 months for the first 2 years and then annually for 5 years.