The effect of intravesical mitomycin C on recurrence of newly diagnosed superficial bladder cancer: A further report with 7 years of followup

Purpose: We determined the role, if any, of 1 and 5 instillations of intravesical mitomycin C in the treatment of newly diagnosed superficial bladder cancer. Materials and Methods: A multicenter randomized clinical trial was done involving 502 patients with newly diagnosed superficial bladder cancer. After complete transurethral resection patients were randomized into 1 of 3 treatment arms: no further treatment, 1 instillation of mitomycin C at resection and 1 instillation at resection and at 3-month intervals for 1 year (total 5 instillations). The dose of mitomycin C used was 40 mg./40 ml. water. End points were interval to first superficial recurrence, recurrence rate (defined as the number of positive cystoscopies per year) and progression-free interval rate (progression defined as the development of muscle invasive or metastatic disease, or death from bladder cancer). Results: After a median followup of 7 years 1 and 5 instillations of mitomycin C resulted in decreased recurrence rates and increased recurrence- free interval. The benefit of mitomycin C was observed in patients at low, medium and high risk for subsequent recurrence. There was suggestive but not conclusive evidence that 5 instillations of mitomycin C offered a slight advantage over 1 instillation. Conclusions: Our analysis confirms the positive benefit of mitomycin C to decrease the number of subsequent recurrences and increase the recurrence-free interval.