How effective is topical alpha-2b interferon in preventing recurrence of superficial bladder cancer?

A total of 44 patients with low and intermediate grade superficial urothelial bladder cancer Ta and T1 were randomised into a controlled, long-term, phase III trial on topical instillation therapy with high dose alpha-2b interferon (100 x 10(6) IU versus low dose alpha-2b interferon (10 x 10(6) IU) versus ethoglucid. Thirteen patients in the low dose group, 11 in the high dose group and 10 in the ethoglucid group completing the trial were evaluable (median follow-up 36.5 months) and were followed up for 3 years. They were treated weekly for 10 weeks and then monthly for a total of 1 year. The aim of the trial was to establish the prophylactic efficacy and the toxic side effects, if any, of alpha-2b interferon in the topical treatment of superficial bladder cancer. Recurrence rate and disease-free survival were chosen as study end-points. The recurrence rate was 4.4 in the low dose interferon group, 2.76 in the high dose interferon group and 3.08 in the ethoglucid group. In the low dose interferon group the time to the first recurrence was 22.23 months versus 22.36 in the high dose group and 21.76 months in the ethoglucid group. No differences of statistical significance were noted between the 3 groups. Progression occurred in 5 patients on interferon but was not seen in those on ethoglucid. Neither systemic nor local side effects were seen in the interferon groups, but 3 patients had to be taken off ethoglucid because of severe chemocystitis. In superficial bladder cancer, topical instillation therapy with interferon is as effective as conventional chemotherapy and has no side effects.