SarCNU in Treating Patients With Recurrent or Metastatic Colorectal Cancer

DISEASE CHARACTERISTICS: Histologically confirmed colorectal cancer Locally recurrent or metastatic disease Previously treated with 1 chemotherapy regimen for recurrent or metastatic disease At least 1 unidimensionally measurable lesion At least 20 mm by conventional techniques OR At least 10 mm by spiral CT scan No prior radiotherapy to indicator lesion (clear disease progression or new lesion within a prior radiation port is acceptable) PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: Absolute granulocyte count at least 1,500/mm^3 Platelet count at least 120,000/mm^3 Hepatic: Bilirubin normal AST and ALT no greater than 2.5 times upper limit of normal Renal: Creatinine normal OR Creatinine clearance at least 60 mL/min Cardiovascular: No symptomatic congestive heart failure No unstable angina pectoris No cardiac arrhythmia Pulmonary: DLCO at least 80% predicted FVC at least 80% predicted No history of significant pulmonary disease No concurrent symptomatic pulmonary disease (e.g., chronic obstructive pulmonary disorder, chronic asthma) Other: No other malignancy within the past 5 years except adequately treated nonmelanoma skin cancer or curatively treated carcinoma in situ of the cervix No other serious illness or medical condition that would preclude study No ongoing or active uncontrolled infection No history of significant neurologic or psychiatric disorder that would preclude study Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 3 months after study PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior immunotherapy No concurrent immunotherapy Chemotherapy: See Disease Characteristics Prior adjuvant chemotherapy allowed No prior nitrosoureas No prior second-line chemotherapy for recurrent or metastatic disease At least 4 weeks since prior chemotherapy No other concurrent chemotherapy Endocrine therapy: No concurrent corticosteroids Radiotherapy: See Disease Characteristics Prior radiotherapy as part of primary therapy allowed At least 4 weeks since prior radiotherapy No concurrent radiotherapy Surgery: Prior surgery as part of primary therapy allowed Prior reoperation for recurrent disease allowed At least 2 weeks since prior surgery other than biopsy Other: At least 4 weeks since prior investigational agent No other concurrent investigational agents or therapy No other concurrent anticancer therapy