Inclusion Criteria

DISEASE CHARACTERISTICS:

- Curatively treated stage I-IV (including stage IVA and IVB) squamous cell carcinoma
of the upper aerodigestive tract of 1 of the following primary sites:

- Oral cavity

- Oropharynx

- Hypopharynx

- Larynx

- Disease-free for at least 6 months and no more than 3 years after completion of
surgery, radiotherapy, and/or chemotherapy

- No synchronous tumors

PATIENT CHARACTERISTICS:

Age

- 18 and over

Performance status

- Karnofsky 70-100% OR

- Zubrod 0-1

Life expectancy

- At least 6 months

Hematopoietic

- Hemoglobin ≥ 10 g/dL

- WBC ≥ 3,000/mm^3

- Platelet count ≥ 100,000/mm^3

Hepatic

- Bilirubin ≤ 1.5 mg/dL

- SGOT ≤ 40 U/L

- SGPT ≤ 56 U/L

Renal

- Creatinine ≤ 1.5 mg/dL

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No other malignancy within the past 5 years except curatively treated head and neck
squamous cell carcinoma, nonmelanoma skin cancer, or carcinoma in situ of the cervix

- No other serious medical or psychiatric illness that would preclude giving informed
consent

- No nausea ≥ grade 2

PRIOR CONCURRENT THERAPY:

Biologic therapy

- Not specified

Chemotherapy

- See Disease Characteristics

- More than 6 months and less than 3 years since prior chemotherapy

- No concurrent chemotherapy

- No other concurrent chemopreventive agents

Endocrine therapy

- More than 6 months and less than 3 years since prior hormonal therapy

Radiotherapy

- See Disease Characteristics

- More than 6 months and less than 3 years since prior radiotherapy

- No concurrent radiotherapy

Surgery

- See Disease Characteristics

- More than 6 months and less than 3 years since prior surgery

- No concurrent surgery

Other

- More than 6 months and less than 3 years since prior investigational agents

- More than 2 months since prior high-dose vitamins (i.e., 10 times the recommended
daily allowance [8,000-10,000 IU of vitamin A, 600 mg of vitamin C, or 80-100 IU of
vitamin E])