Long-term observation after intravesical metaphylaxis with mitomycin C in patients with superficial bladder tumors

Long-term follow-up of patients with superficial transitional cell carcinoma of the urinary bladder treated by intravesical mitomycin C

Prophylactic intravesical chemotherapy (IVC) reduces recurrence rates of superficial transitional cell carcinoma (TCC) of the urinary bladder. The patient cohort existed of 86 individuals (stage TaN0M0 or T1N0M0) superficial carcinoma of various grades of malignancy. Following initial transuretheral resection or diagnostic cystoscopy, mitomycin C (MMC), 20 mg dissolved in 50 ml saline, was instilled intravesically by catheter over 1 hr at 2-week intervals, initially and then four more times followed by diagnostic cystoscopy (one course = 12 weeks). Two similar courses were administered thereafter for a total period of 36 weeks. For patients in remission, installations continued in monthly fractionations for 9 more months (cystoscopy every 3 months) and then at 2-month intervals for 12 more months (cystoscopy every 6 months). When cystoscopy revealed recurrence, IVC was repeated from the beginning. No symptoms of MMC-related toxicity were observed. Cystoscopic follow-up evaluations showed a complete response rate of 84% at 3 years and 81% at 5 years after initial therapy. Twenty-seven patients who had not responded to previous treatment with other drugs responded to MMC.

Bladder damage in mice after single and repeated intravesical instillations of mitomycin C or doxorubicin

Functional and histological damage after intravesical administration of mitomycin C or doxorubicin were studied in mouse bladders. Dosing schedules were based on those commonly used in the clinic, and bladder function was assessed from changes in urination frequency. Repeated weekly instillations of 1 mg./ml. mitomycin C induced a transient three-fold increase in Frequency Index (FI) with recovery to control levels within 3 weeks. Weekly instillations of 6 mg./ml. doxorubicin also resulted in a three-fold increase in FI, but lower doses produced only minimal changes. There was, again, full recovery within 3 weeks. Our experiments indicate that repeated intravesical instillations of mitomycin C or doxorubicin are well tolerated, with rapid recovery from functional damage within a few weeks of cessation of therapy. There was significantly less damage after repeated instillations of clinically relevant doses of doxorubicin than mitomycin C.

Mitomycin-C in superficial bladder cancer. Is long-term maintenance therapy worthwhile after initial treatment?

A total of 72 patients with recurrent superficial transitional cell carcinoma of the bladder (TCC) were treated with 40 mg intravesical instillations of mitomycin-C (MMC) weekly for 10 weeks, followed by monthly maintenance doses. With a mean follow-up period of 41 months, 30 patients (42%) had a complete and sustained response after the initial treatment course, and a further 14 (19%) achieved a complete response on maintenance therapy. Sixteen patients (22%) continued to have recurrent tumours and the remaining 12 (17%) developed recurrent tumours after an initial complete response. Of these, 4 patients with carcinoma in situ (CIS) showed symptomatic improvement, but the histological changes persisted and all of those with tumours > 2 cm in size did not respond. We conclude that maintenance treatment with MMC is beneficial in superficial bladder cancer but is of limited value in the presence of bulky tumours or CIS.