High-Dose Fluorouracil With or Without Leucovorin Compared With Standard Fluorouracil Plus Leucovorin Following Surgery in Treating Patients With Stage III Colon Cancer

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. It is not yet known which chemotherapy regimen is more effective for colon cancer.
PURPOSE: This randomized phase III trial is studying high-dose fluorouracil with or without leucovorin to see how well it works compared to standard-dose fluorouracil and leucovorin in treating patients who have undergone surgery for stage III colon cancer.