Renal complications of mitomycin C therapy with special reference to the total dose.

One hundred forty-two patients with gastrointestinal cancer were treated with combination chemotherapy containing mitomycin C. The mitomycin C dose was less than or equal to 15 mg/m2 every 53rd day and the total cumulative dose was between 25 and 250 mg. Ten of the evaluable 118 patients (8.5%) developed renal toxicity due to mitomycin C. Five of these ten patients had microangiopathic hemolytic anemia, too. Six of them died 2 to 4.5 months after the last mitomycin C dose and four are alive 14 to 30 months after the last dose. Only 1 of the 63 patients (1.6%) who received less than 50 mg/m2 mitomycin C developed renal toxicity. Four of the 37 patients (10.8%) who received 50 to 69 mg/m2 and 5 of 18 (27.8%) who received more than 70 mg/m2 of mitomycin C developed nephrotoxicity. The toxicity of mitomycin C seems to be dose related, the safe total dose being less than 50 mg/m2 if delivered in doses of 10 to 15 mg/m2 at 8-week intervals.