Effect of intravesical instillation of antitumor drugs in the development of N-butyl-N-(4-hydroxybutyl) nitrosamine-induced bladder tumors in rats.

We examined the effects of intravesical instillation of adriamycin (ADM) and cis-diammine-dichloroplatinum (CDDP) on the development of bladder tumors induced by 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine in 115 rats. Intravesical instillation was performed in two ways; continuous administration (5 times a week for 5 weeks) and intermittent administration (once a week). Group 1 (control group) did not receive intravesical instillation. Group 2 I(ADM), group 3 (CDDP) and group 4 (physiological saline) were continuous type. Group 5 (ADM), group 6 (CDDP) and group 7 (physiological saline) received intermittent administration. Bladder weight was significantly higher in group 4 than in groups 1 or 7, and that in groups 2 and 3 than that in group 5 and 6. In groups 2, 3, 5 and 6 bladder weight was almost normal or higher than in the control group, and in group 3 histologically cancer was not seen in one rat. Physiological saline had promoting activity, and ADM and CDDP had both inhibitory and promoting activities. Also, intravesical instillation itself was suggested to promote tumor development under carcinogenic circumstances. We conclude that intermittent intravesical instillation should be performed to inhibit tumor recurrence and intravesical instillation therapy should not be performed clinically for a long period.