Isolated Hepatic Perfusion With Melphalan Followed by Combination Chemotherapy in Treating Patients With Unresectable Liver Metastases From Colorectal Cancer

RATIONALE: Drugs used in chemotherapy, such as melphalan, leucovorin, oxaliplatin, and fluorouracil, 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) and giving the drugs in different ways may kill more tumor cells. PURPOSE: This phase II trial is studying how well isolated hepatic perfusion with melphalan followed by combination chemotherapy works in treating patients with unresectable liver metastases from colorectal cancer.