Isolated Hepatic Perfusion With Melphalan Followed By Chemotherapy in Treating Patients With Unresectable Colorectal Cancer That is Metastatic to the Liver

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining more than one drug and giving them in different ways may kill more tumor cells.
PURPOSE: Phase II trial to study the effectiveness of melphalan given as an isolated hepatic perfusion followed by chemotherapy infused into the liver in patients who have unresectable colorectal cancer that is metastatic to the liver.