Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically confirmed colorectal adenocarcinoma

- Metastatic or locally advanced disease

- Not amenable to curative therapy

- Documentation of disease progression within the past 6 months

- Previously treated with fluoropyrimidine- and irinotecan-based chemotherapy
(including capecitabine) administered either concurrently (no more than 2 regimens)
or sequentially (no more than 3 regimens) for advanced disease

- At least 1 unidimensionally measurable lesion

- At least 20 mm by conventional techniques OR at least 10 mm by spiral CT scan

- No known brain metastases

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- ECOG 0-2 OR

- Karnofsky 60-100%

Life expectancy:

- More than 12 weeks

Hematopoietic:

- Absolute neutrophil count at least 1,500/mm^3

- Platelet count at least 100,000/mm^3

Hepatic:

- Bilirubin no greater than 1.5 times upper limit of normal (ULN)

- AST/ALT no greater than 3 times ULN (5 times ULN if liver metastasis present)

Renal:

- Creatinine no greater than 1.5 times ULN OR

- Creatinine clearance at least 60 mL/min

Cardiovascular:

- No symptomatic congestive heart failure

- No unstable angina pectoris

- No cardiac arrhythmia

Ophthalmic:

- No significant ophthalmic conditions, including:

- Severe dry-eye syndrome

- Keratoconjunctivitis sicca

- Sjogren's syndrome

- Severe-exposure keratopathy

- Disorders that may increase the risk for epithelium-related complications (e.g.,
bullous keratopathy, aniridia, severe chemical burns, or neutrophilic keratitis)

Other:

- Able to take oral gefitinib

- No other uncontrolled concurrent illness

- No ongoing or active infection

- No psychiatric illness or social situation that would preclude study participation

- No prior gastrointestinal disorders (e.g., malabsorption syndrome)

- No prior allergic reactions attributed to compounds of similar chemical or biological
composition to gefitinib

- No other prior malignancy except carcinoma in situ of the cervix, nonmelanoma skin
cancer, or other cancer from which the patient has been free of evident disease for
more than 5 years and/or has less than a 20-30% estimated likelihood of recurrence

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Not specified

Chemotherapy:

- See Disease Characteristics

- At least 30 days since prior chemotherapy and recovered

Endocrine therapy:

- Not specified

Radiotherapy:

- Not specified

Surgery:

- No prior gastric resection

Other:

- No other prior therapy for advanced disease

- No concurrent combination antiretroviral therapy for HIV-positive patients

- No other concurrent investigational or commercial agents or therapies for the
malignancy