[Investigation of retention time of intravesical instillation therapy with pirarubicin (THP)].

The effective and less side effect retention time of intravesical instillation therapy with Pirarubicin (THP) was investigated for the treatment of urinary bladder tumor. Fifty-seven cases of urinary bladder tumor were treated by intravesical instillation therapy with THP (20 mg/40 ml) a total of 6 times, with the first instillation at the time of surgery and the other 5 at a rate of three times a week thereafter. The retention time was 30 minutes, and it was allowed to last 10 or 60 minutes for comparison in some cases. Tumor and normal tissue were examined in the first instillation, and normal tissue in the sixth instillation. Infiltration to the bladder wall of THP was observed under fluorescence microscopy. Although the amount of tumor uptake was larger than normal tissue in the first instillation, no satisfactory infiltration was obtained. Repeated administration of THP with the retention time of 30 minutes enhanced the uptake and increased the infiltration in many cases, and side effects were scarcely noted. Retention time of 10 minutes was unsatisfactory, while the retention time of 60 minutes was discontinued in the early stage of treatment due to severe irritative bladder symptoms. Therefore, a retention time of 30 minutes is adequate in the case of repeated administration of THP in a short period.