I. To determine if treatment with cisplatin and volume-directed radiation followed by carboplatin and paclitaxel for 4 cycles (experimental arm) reduces the rate of recurrence or death (i.e., increases recurrence-free survival) when compared to chemotherapy consisting of carboplatin and paclitaxel for 6 cycles (control arm) in patients with stages III-IVA endometrial carcinoma (< 2 cm residual disease) or patients with International Federation of Gynecology and Obstetrics (FIGO) 2009 stage I or II serous (uterine papillary serous carcinoma [UPSC]) or clear cell endometrial carcinoma and positive cytology.