EFFECTIVENESS OF A SINGLE IMMEDIATE MITOMYCIN C INSTILLATION IN PATIENTS WITH LOW RISK SUPERFICIAL BLADDER CANCER: SHORT AND LONG-TERM FOLLOWUP

Abstract

PURPOSE: We analyze the impact of a single mitomycin C instillation in patients with low risk superficial bladder cancer with short and long-term followup. MATERIALS AND METHODS: A total of 131 patients with low risk superficial bladder cancer were included in a prospective randomized controlled trial. All patients had a 3 cm or less single, papillary, primary or recurrent tumor and were disease-free for more than 1 year. Patients with muscular invasion, G3 tumor or bladder carcinoma in situ on pathological examination were excluded from study. The tumor was completely resected before patients were randomized into 2 arms of no further treatment (control group) and a single immediate instillation of 30 mg mitomycin C (mitomycin C group). Recurrences were considered early within the first 2 years of followup. RESULTS: At 24-month followup the recurrence-free interval was significantly increased, and recurrence, and recurrence and tumor per year rates were decreased in the mitomycin C compared to the control group. However, at long-term followup these differences were not statistically significant and the recurrence-free interval curves were parallel. A shorter hospital stay and catheterization period were noted in the mitomycin C group compared to the control group, which were not significant. Early recurrences were concentrated in the first year in the control but not in the mitomycin C group. A significant relationship between early and late recurrences was found in the mitomycin C but not in the control group. CONCLUSIONS: Our analysis confirms the positive effect of a single immediate mitomycin C instillation in patients with low risk superficial bladder cancer. This benefit is limited to early recurrence and is not maintained with long-term followup. Thus, this approach is an alternative to observation or endovesical chemotherapy. Our study also suggests that cell implantation as a mechanism of early recurrence can be controlled with a single mitomycin C instillation.