Combination Chemotherapy in Treating Patients With Metastatic Colorectal Cancer

DISEASE CHARACTERISTICS: Diagnosis of metastatic colorectal carcinoma Bidimensionally measurable disease PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: WBC at least 4,000/mm^3 Granulocyte count at least 1,500/mm^3 Absolute neutrophil count at least 1,500/mm^3 Platelet count at least 100,000/mm^3 Hemoglobin greater than 8 g/dL Hepatic: Bilirubin no greater than 1.2 mg/dL AST and ALT less than 2.5 times upper limit of normal (ULN) PT no greater than ULN (not on anticoagulation therapy) Renal: Creatinine no greater than 1.5 mg/dL Creatine clearance greater than 60 mL/min Pulmonary: DLCO at least 60% Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 2 months after study No other concurrent active malignancies Prior malignancies presumed to be cured allowed No other concurrent uncontrolled severe medical problem that would preclude study participation PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 6 months since prior adjuvant chemotherapy without disease recurrence No more than 1 prior chemotherapy regimen for metastatic disease Endocrine therapy: Not specified Radiotherapy: Prior adjuvant radiotherapy allowed No prior radiotherapy to more than 25% of total bone marrow Surgery: Not specified Other: No other prior therapy for advanced disease