Irinotecan With or Without Capecitabine as Second-Line Therapy in Treating Older Patients With Progressive, Metastatic Colorectal Cancer That Cannot Be Removed By Surgery

RATIONALE: Drugs used in chemotherapy, such as irinotecan and capecitabine, 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. It is not yet known whether irinotecan and capecitabine are more effective than irinotecan alone in treating colorectal cancer.
PURPOSE: This randomized phase II trial is studying irinotecan and capecitabine to see how well they work as second-line therapy compared to irinotecan alone in treating older patients with progressive, metastatic colorectal cancer that cannot be removed by surgery.