Inclusion Criteria

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