High-Dose Multivitamins Compared to a Placebo in Preventing the Recurrence of Cancer in Patients With Early Stage Bladder Cancer

DISEASE CHARACTERISTICS: Histologically confirmed stage 0 and I (Ta, T1 or Tis) resected transitional cell carcinoma of the bladder No advanced disease or muscle invasion No history of transitional cell carcinoma of the prostate PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Not specified Life expectancy: Greater than 3 years Hematopoietic: WBC at least 3500/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 10 g/dL Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) Alkaline phosphatase no greater than 3 times ULN SGOT no greater than 3 times ULN Renal: Creatinine no greater than 1.5 times ULN Other: Not pregnant or nursing Fertile patients must use effective contraception At least 5 years since prior malignancy except nonmetastatic squamous cell or basal cell carcinoma of the skin No history of drug interactions which could affect therapy No immunodeficiency PRIOR CONCURRENT THERAPY: Biologic therapy: Prior intravesical BCG required (if T1 or Tis pathology and negative cytology PAB) Chemotherapy: Not specified Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy to the pelvis Surgery: Not specified Other: Intravesical therapy within 30 days allowed At least 30 days since greater than 2 multivitamins daily