[Therapeutic effect of mitomycin C in the immediate postoperative period in patients with intermediate-risk non-muscle-invasive bladder tumors]. / Efecto terapéutico de mitomicina C en el postoperatorio inmediato de pacientes con tumores vesicales no músculo invasores de riesgo intermedio.

INTRODUCTION: Approximately 70-85% of transitional bladder cell carcinomas are non-muscle-invasive. After an initial surgery, around 60-90% will have a recurrence, being the highest risk period the first two years. Urothelium instability could be the main reason for recurrence in mid grade tumours, reason why a single dose of a chemotherapy after transurethral resection of the bladder (TURB) might be insufficient. That is why a deferred therapy in occasions associated with maintenance is recommended. PATIENTS AND METHODS: A prospective, controlled and randomized study was performed. We included non-muscle-invasive mid risk bladder tumours. All patients had initially a TURB performed and were randomized to receive a single dose of mitomycin C (MMC), in the immediate postoperative period. RESULTS: A total of 105 patients were included. Mean follow-up was 22, 70 +/- 8, 15 months. MMC was administered to 53 patients. Of these 66, 0% had no recurrence and 34.0% had a non-muscle-invasive recurrence. Of the 52 patients in the non MMC group, 53.8% had no recurrence and 44.2% had a non-muscle-invasive recurrence and only 1 patient had a muscle-invasive progression. We did not find significantly differences in time to recurrence in mid risk tumours when using immediate postoperative single dose of MMC or deferred therapy. There was only one case of myelosuppression. DISCUSSION: In mid risk non-muscle-invasive tumors, some studies suggest that early intravesical instillation of chemotherapy reduces the risk of recurrence after TURB. We could not show significantly differences when comparing postoperatorive MMC versus traditional deferred instillations.