Combination Chemotherapy and Bevacizumab 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. 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. Bevacizumab may also stop the growth of tumor cells by blocking blood flow to the tumor. Giving combination chemotherapy together with bevacizumab may kill more tumor cells. PURPOSE: This phase II trial is studying the side effects of giving combination chemotherapy together with bevacizumab and to see how well it works in treating patients with metastatic colorectal cancer.