Does intravesical chemotherapy prevent invasive bladder cancer?

Intravesical chemotherapy has been shown to prolong the interval free of disease and to reduce the tumor recurrence rates in patients with superficial bladder cancer. These observations led us to consider whether a course of intravesical chemotherapy might provide a long-term decrease in the recurrent tumor rate or reduce the incidence of progression to invasive carcinoma. The records of 123 patients entered into a randomized multicenter protocol between 1975 and 1978 were examined. Patients had received a 1-year course of thiotepa or VM26, or transurethral resection alone. Mean followup was 47 months. Patients receiving thiotepa or VM26 had a lower rate of tumor recurrence, expressed as recurrences per 100 patient-months, than those undergoing transurethral resection only (5.25 versus 5.71 versus 7.98) but this was not statistically significant. However, 28 per cent of the controls required therapy besides transurethral resection to control the bladder cancer and 19 per cent died of advanced bladder cancer during followup. Only 15 per cent of the patients undergoing intravesical chemotherapy required therapy other than transurethral resection and only 3 per cent died of advanced carcinoma of the bladder. This finding suggests that intravesical chemotherapy given for 1 year is associated with a significant decrease in the incidence of tumor progression, and provides the justification to conduct future trials with extended followup.