Combination Chemotherapy With or Without Cetuximab as First-Line Therapy in Treating Patients With Metastatic Colorectal Cancer

RATIONALE: Drugs used in chemotherapy work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving more than one drug (combination chemotherapy) may kill more tumor cells. Monoclonal antibodies, such as cetuximab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. It is not yet known whether combination chemotherapy and cetuximab are more effective than combination chemotherapy alone in treating colorectal cancer. PURPOSE: This randomized phase III trial is studying combination chemotherapy and cetuximab to see how well they work compared to combination chemotherapy alone as first-line therapy in treating patients with metastatic colorectal cancer.