Mitomycin C-induced renal toxicity, a dose-dependent side effect?

Mitomycin C (MMC) has been known to be nephrotoxic since 1971. Whether this side effect was dose-dependent is unknown, while data on incidence are scanty. The presently-reported prospective study was initiated with the objective to obtain more data on these subjects. Forty-four patients treated with MMC entered the study, 37 were evaluable. All patients were subjected to extensive serial laboratory tests to study renal function and to detect hemolysis or coagulation disorders. The results were evaluated per cumulative dose level. One patient developed a lethal hemolytic uremic syndrome after 40 mg/m² MMC. None of the laboratory tests predicted this side effect. None of the other patients developed renal toxicity, while all laboratory tests remained within normal ranges. All available literature on this subject was also reviewed. Based on the results of the present study, as well as on the literature review, it is concluded that MMC-related renal toxicity is a dose-dependent side effect, occurring at cumulative dose levels of 30 mg/m² or more. The incidence is likely to be less than 10%. Predictive laboratory test could not be indicated.