[Appropriate intravesical retention time of pirarubicin concentration based on its level in tumor tissue, anti-tumor effect and side effect in intravesical instillation therapy for bladder tumor].

The present study was designed to investigate the appropriate intravesical retention time of pirarubicin (THP) for the treatment of bladder tumor in terms of its anti-tumor effect and side effect. We administered THP to 22 patients with superficial bladder tumor intravesically and measured the THP concentration in the tumor tissues. Patients were divided into 3 groups by retention time; 8 for 30 minutes, 8 for 1 hour and 7 for 2 hours. Tumor tissues were obtained by transurethral resection 30 min., 1 or 2 hours after the intravesical instillation of THP at the fixed concentrations of 30 mg/30 ml. There was no significant difference in THP concentration between 3 groups. This indicates that the anti-tumor effect of intravesical instillation of the THP would be expected by only 30 min. of intravesical retention time at the THP concentration of 30 mg/30 ml. Then, we administered 30 mg/30 ml of THP solution for 30 min. to 10 patients intravesically 6 times every 48 hours to investigate its clinical anti-tumor effect and side effect. There were 2 complete responses, 3 partial responses and 5 cases with no changes for a total response rate of 50%. No side effect was observed. It is considered that 30 min. of intravesical retention time at the THP concentration of 30 mg/30 ml would be appropriate in terms of its anti-tumor effect and side effect.