PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Not specified Hepatic: Bilirubin no greater than 1.5 mg/dL Renal: Creatinine no greater than 2 times upper limit of normal Cardiovascular: No uncontrolled high blood pressure No unstable angina No symptomatic congestive heart failure No uncontrolled cardiac arrhythmias No myocardial infarction in past 6 months Other: No other malignancy within the past 5 years except basal cell skin cancer No uncontrolled diabetes mellitus or inability to tolerate high sugar content of green tea at discretion of oncologist No other medical or psychiatric conditions that would preclude study