 - Arm I: Patients receive leucovorin calcium IV and fluorouracil 5-FU IV on days 1-5 of courses 1, 3, and 4. Courses repeat every 28 days. During course 2, patients undergo radiotherapy 5 days a week and receive 5-FU IV continuously for 5 weeks. Patients rest for 28-35 days between course 2 and 3. 