Selenium in Preventing Cancer Recurrence in Patients With Bladder Cancer

DISEASE CHARACTERISTICS: Histopathologically confirmed non-muscle-invasive transitional cell carcinoma (TCC) of the bladder (\< pT2 ) PATIENT CHARACTERISTICS: * Able to swallow pills * Not pregnant * Fertile patients must use effective contraception * No other malignancy within the past 5 years * No known hypersensitivity or adverse reactions to selenium * No other serious medical or psychiatric illness that would preclude giving informed consent * No condition that, in the opinion of the investigator, may interfere with the safety of the patient or the evaluation of the study objectives PRIOR CONCURRENT THERAPY: * See Disease Characteristics * More than 30 days since prior daily dietary supplements containing selenium * No other concurrent selenium (contained in individual supplements, antioxidant mix, or multivitamin) intake * No concurrent participation in another study involving a medical, surgical, nutritional, or lifestyle intervention * Concurrent participation in the follow-up phase of another study allowed