Combination Chemotherapy for 3 Months or 6 Months in Treating Patients With Stage III Colon Cancer

RATIONALE: Drugs used in chemotherapy, such as oxaliplatin, leucovorin calcium, and fluorouracil, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. It is not yet known whether giving more than one drug (combination chemotherapy) is more effective when given for 3 months or 6 months in treating patients with colon cancer.
PURPOSE: This randomized phase III trial is studying giving combination chemotherapy for 3 months to see how well it works compared with giving combination chemotherapy for 6 months in treating patients with stage III colon cancer.