S-1 and Bevacizumab in Treating Patients With Colorectal Cancer That is Recurrent or Cannot Be Removed by Surgery

RATIONALE: Drugs used in chemotherapy, such as S-1, 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. Giving S-1 together with bevacizumab may kill more tumor cells.
PURPOSE: This phase II trial is studying how well giving S-1 together with bevacizumab works as third-line therapy in treating patients with colorectal cancer that is recurrent or that cannot be removed by surgery.