Bevacizumab and Combination Chemotherapy in Treating Patients With Previously Untreated Metastatic Colorectal Cancer That Cannot Be Removed By Surgery
RATIONALE: Monoclonal antibodies, such as bevacizumab, 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. 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 bevacizumab together with combination chemotherapy may kill more tumor cells. PURPOSE: This phase III trial is studying how well giving induction therapy with bevacizumab together with combination chemotherapy with or without capecitabine followed by bevacizumab maintenance therapy in treating patients with metastatic colorectal cancer that cannot be removed by surgery.