Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed squamous cell carcinoma of the head and neck, including 1 of
the following primary tumor sites:

- Oral cavity

- Oropharynx

- Nasopharynx

- Hypopharynx

- Larynx

- Unknown primary

- Any disease stage allowed

- No evidence of active disease

- Must have undergone curative surgical resection, radiotherapy, and/or chemotherapy at
least 1 month, but no more than 4 years ago

PATIENT CHARACTERISTICS:

Performance status

- Karnofsky 70-100%

Life expectancy

- More than 3 months

Hematopoietic

- WBC ≥ 3,000/mm^3

- Granulocyte count ≥ 1,500/mm^3

- Platelet count ≥ 100,000/mm^3

Hepatic

- Bilirubin ≤ 1.5 times upper limit of normal (ULN)

- AST or ALT ≤ 2.5 times ULN

- Alkaline phosphatase ≤ 2.5 times ULN

- Hepatitis B and/or C negative

Renal

- Creatinine clearance > 50 mL/min

Cardiovascular

- No myocardial infarction within the past 12 months

- No uncontrolled congestive heart failure

- No unstable or uncontrolled angina

Gastrointestinal

- No lack of physical integrity of the upper gastrointestinal tract

- Must be able to swallow tablet

- No malabsorption syndrome

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- HIV negative

- No other malignancy within the past 5 years except adequately treated basal cell or
squamous cell skin cancer, carcinoma in situ of the cervix, or stage I or II cancer
for which the patient is currently in complete remission

- No history of uncontrolled seizures, CNS disorders, or psychiatric disability that
would preclude study compliance or giving informed consent

- No ongoing postoperative fistula

- No prior unanticipated severe reaction to fluoropyrimidine therapy or known
sensitivity to fluorouracil

- No other serious uncontrolled medical or surgical condition that would preclude study
participation

PRIOR CONCURRENT THERAPY:

Chemotherapy

- See Disease Characteristics

- Prior oral fluoropyrimidine therapy allowed provided it was given in the adjuvant
setting and completed ≥ 12 months ago

Radiotherapy

- See Disease Characteristics

Surgery

- See Disease Characteristics

- More than 4 weeks since prior major surgery and recovered

- No prior organ allografts

Other

- More than 4 weeks since prior participation in any investigational drug study