OUTLINE: This is a randomized study. Patients are randomized to 1 of 2 treatment arms. Arm I: Patients receive a single dose of carboplatin IV. Arm II: Patients undergo radiotherapy once daily, 5 days a week. Patients are followed every 3 months for 1 year, every 4 months for 1 year, every 6 months for 1 year, and then annually thereafter.