RATIONALE: Chemoprevention therapy is the use of certain drugs to try to prevent the development or recurrence of cancer. The use of high-dose multivitamins may be an effective way to prevent the recurrence of early stage bladder cancer. It is not yet known whether high-dose vitamins are more effective than no further therapy in decreasing the risk of early-stage bladder cancer.

PURPOSE: Randomized double-blinded phase III trial to compare the effectiveness of high-dose multivitamins with a placebo in preventing the recurrence of cancer in patients with early stage bladder cancer.

OBJECTIVE: I. Determine whether high dose multivitamins have chemopreventive efficacy beyond standard therapy in reducing the risk of recurrence in patients with resected stage 0 and I (Ta, T1, and Tis) transitional cell carcinoma of the bladder.

OUTLINE: This is a randomized, double blind study. Patients are randomized to receive multivitamins or placebo orally once daily for 3 years. Patients are followed every 3 months for 2 years, then every 6 months for 1 year, and then annually thereafter.

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