Irofulven in Treating Patients With Metastatic Colorectal Cancer

DISEASE CHARACTERISTICS: Histologically confirmed metastatic adenocarcinoma of the colon or rectum Bidimensionally measurable lesions Sentinel lesions outside the field of any prior radiation therapy No confirmed or suspected brain metastases PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Zubrod 0-1 Life expectancy: At least 12 weeks Hematopoietic: Granulocyte count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL Renal: Creatinine no greater than 1.5 mg/dL Creatinine clearance at least 60 mL/min Cardiovascular: No active congestive heart failure No uncontrolled angina At least 6 months since prior myocardial infarction No uncontrolled hypertension Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No concurrent serious infection No other malignancy within the past 5 years except nonmelanoma skin cancer or carcinoma in situ of the cervix No overt psychosis or mental disability No life threatening illness (unrelated to tumor) PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent biologic therapy Chemotherapy: No prior chemotherapy for metastatic disease At least 6 months since prior adjuvant chemotherapy No other concurrent chemotherapy Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiation therapy and recovered No concurrent radiotherapy Surgery: At least 4 weeks since prior major surgery and recovered No concurrent surgery Other: At least 28 days since prior administration of any investigational drug No other concurrent anticancer therapy