Intravesical chemotherapy for maximum prophylaxis of new early phase superficial bladder carcinoma treated by transurethral resection - A combined analysis of trials by the Japanese urological cancer research croon using smoothed hazard function

BACKGROUND. The effect of intravesical instillation of doxorubicin or epiru bicin after transurethral resection (TUR) was estimated from the data of fi ve randomized clinical trials in Japan. The authors provided the estimated hazard function plots with a smoothing technique, to evaluate the prophylac tic effect of an intravesical therapy over time and to estimate the natural history of superficial bladder carcinoma. METHODS. Data on a total of 1732 patients from 5 studies of the Japanese Ur ological Cancer Research Group who were eligible to receive doxorubicin and epirubicin were analyzed. The patients were divided into four subgroups ba sed on their background characteristics. Their tumors were categorized as " primary and solitary," "primary and multiple," "recurrent and solitary," or "recurrent and multiple." RESULTS. Multivariate analysis revealed that intravesical instillation redu ced the risk of recurrence to about one-half to two-thirds compared with th e controls. The shapes of the graphs that estimated the hazard function for patients with no prophylaxis indicated that multiple tumors showed an earl ier peak of recurrence than solitary tumors and recurrent tumors had a high er hazard of recurrence than primary tumors. Graphic presentation of the ha zard function in each subgroup suggested that the effect of prophylaxis con tinued for 500 days after TUR but not for longer. CONCLUSIONS. This analysis indicated that there are two patterns of tumor r ecurrence of superficial bladder carcinoma after TUR, namely, early phase a nd late phase. Intravesical chemotherapy may be effective mainly in reducin g the hazard for recurrence in the early phase. (C) 1999 American Cancer So ciety.