Irinotecan and Celecoxib in Treating Patients With Unresectable or Metastatic Colorectal Cancer

RATIONALE: Drugs used in chemotherapy, such as irinotecan, work in different ways to stop tumor cells from dividing so they stop growing or die. Celecoxib may stop the growth of tumor cells by blocking the enzymes necessary for their growth. Giving irinotecan with celecoxib may kill more tumor cells.
PURPOSE: This phase I trial is studying the side effects and best dose of irinotecan when given with celecoxib in treating patients with unresectable or metastatic colorectal cancer.