Combination Chemotherapy With or Without Irinotecan 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. Combining more than one drug may kill more tumor cells. It is not yet known if combination chemotherapy is more effective with or without irinotecan in treating colon cancer.
PURPOSE: Randomized phase III trial to compare the effectiveness of combination chemotherapy with or without irinotecan in treating patients who have stage III colon cancer.