Intravesical instillation of beta-interferon in the treatment of bladder cancer.

A total of 36 patients with single superficial bladder cancer TNM stage Ta-T1/G2 was studied over a 24-month period before entering the study to evaluate the efficacy and tolerance of high doses of beta-interferon (beta-INF); 24 patients had a primary tumour (group 1) and 12 had had more than 3 recurrences (group 2). They received 8 intravesical doses of beta-INF, 50,000,000 IU in 50 ml sterile water, at weekly intervals, 15 days after transurethral resection of the bladder (TURB). Efficacy was estimated by simple recurrence rate and by the person-years method. The recurrence rate was 25% in group 1 with a mean follow-up of 21.6 months. Comparison with the recurrence rate of a historical control group treated only by TUR showed that there was a slight statistically significant difference. Group 2 had a recurrence rate of 100% in the period before beta-INF (follow-up 24 months) and 91% after INF administration (mean follow-up 20.5 months). Patients were questioned about side effects before and after each treatment; tolerance of the drug was excellent. The results suggest that beta-interferon could be safely used as a prophylactic agent against the recurrence of primary superficial bladder cancer. Its efficacy seems comparable to that obtained with other current chemoprophylactic agents.