Purpose: Interferons have shown a definite activity in the intravesical treatment of residual papillary bladder cancer or carcinoma in situ (CIS). The purpose of the present study was to investigate the efficacy of interferon alfa-2b (IFN) as prophylactic treatment of superficial bladder cancer.
Patients and methods: Two hundred eighty-seven patients with primary pTa G2, pT1 G1 to G2 superficial bladder cancer, following complete transurethral resection (TUR), were randomly allocated to receive intravesical treatment, either with IFN (50 x 10(6) IU) or mitomycin (MIT-C; 40 mg). Drugs were instilled on a weekly basis for a total of 8 weeks.
Results: MIT-C was superior to IFN treatment with respect to time to recurrence, relative recurrence rate, recurrence rate per 100 patients per month, and recurrence tumor rate per 100 patients per month. This difference was particularly evident in patients with pTa G2 tumors. After multivariate analysis, the number of primary tumors and tumor grade were the best predictors of recurrence, while allocated treatment had only a moderate effect. Intravesical treatment was well tolerated in both arms. However, more local toxicity was experienced by patients treated with MIT-C. On the other hand, fever occurred significantly more frequently in patients treated with IFN.
Conclusion: IFN was less effective, although locally better tolerated, than MIT-C as prophylactic treatment of primary superficial bladder cancer.