Brief Summary: This pilot clinical trial studies radiation therapy, paclitaxel, and carboplatin in treating patients with uterine cancer. Radiation therapy uses high-energy x-rays to kill tumor cells. Drugs used in chemotherapy, such as paclitaxel and carboplatin, work in different ways to stop the growth of tumor cells, either by killing the cells or stopping them from dividing. Giving radiation with chemotherapy may kill more tumor cells.

Detailed Description: PRIMARY OBJECTIVES: I. To assess the one year recurrence-free survival in patients with uterine carcinosarcoma treated with "sandwich" therapy-including defining the patterns of recurrence in patients with carcinosarcoma who were treated with this regimen. II. To evaluate the toxicity and tolerability of pelvic radiation "sandwiched" between cycles of paclitaxel/carboplatin chemotherapy in patients with uterine carcinosarcoma. III. To correlate surrogate endpoint biomarkers with progression-free survival and prognosis. OUTLINE: CHEMOTHERAPY (weeks 1-9, 14-22): Patients receive paclitaxel intravenously (IV) over 3 hours and carboplatin IV over 30 minutes on day 1. Treatment repeats every 21 days for 3 courses during weeks 1-9 and 14-22. RADIATION THERAPY (weeks 8-16): Patients undergo external beam pelvic radiation therapy once a day, 5 days a week for 5 weeks during weeks 8-13. Patients then undergo high dose radiation (HDR) brachytherapy or intensity-modulated radiation therapy (IMRT) once weekly during weeks 14-16. After completion of study treatment, patients are followed up every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.