Patients with endometrial cancer are typically treated with radiation and chemotherapy.  Today most women with endometrial cancer whose cancer has spread outside the uterus generally receive chemotherapy.  Women who have disease outside the uterus may also receive radiation to the areas where the disease has spread. It is not clear whether giving chemotherapy alone or together with radiation is the best treatment.  This study is being conducted to determine if radiation therapy combined with chemotherapy administered for a total of 4 cycles offers a benefit over chemotherapy alone administered over 6 cycles (one cycle is 3 weeks on study treatment).

This study will compare the effects of two treatments in patients with endometrial cancer contained in the abdomen. One treatment, which is considered experimental, consists of cisplatin given together with radiation therapy followed by the drugs carboplatin and paclitaxel for 4 cycles.  Another treatment, the current standard therapy, consists of carboplatin and paclitaxel given for 6 cycles without radiation therapy.   This study will compare survival of patients receiving these two treatments and side effects of both treatments.  In this study, patients will get either cisplatin plus radiation therapy followed by 4 cycles of carboplatin and paclitaxel or 6 cycles of carboplatin and paclitaxel alone.

This study will also collect samples of  tumor tissue (if available from a previous surgery) and blood to find out if special tests can determine which patients may respond to treatment or have a better prognosis, and which patients may have side effects.