Gemcitabine, Capecitabine, and Oxaliplatin as Second-Line Therapy in Treating Patients With Advanced Colorectal Cancer Previously Treated With Irinotecan

RATIONALE: Drugs used in chemotherapy, such as gemcitabine, capecitabine, and oxaliplatin, 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.
PURPOSE: This phase I/II trial is studying the side effects and best dose of gemcitabine when given together with capecitabine and oxaliplatin as second-line therapy and to see how well it works in treating patients with advanced colorectal cancer previously treated with irinotecan.