Chronic anemia due to mitomycin C is drug dose-dependent, normocytic, progressive, related to erythropoietin levels and quantitatively predictable: implications for radiochemotherapy.

ABSTRACT

Mitomycin C (MC) is used as therapy against solid tumors, also combined with other chemotherapeutic agents or radiotherapy. It may cause acute, subacute, or chronic anemia capable of modifying the results of chemo- and radiotherapy. Erythropoietin may be lowered by cancer itself or because of chemoradiotherapy. There are few studies investigating the relationship between erythropoietin and chronic anemia.We prospectively analyzed the chronic anemia and erythropoietin in 38 patients with solid cancer. Patients were 40 to 82 years of age. MC was randomly given every 3 weeks as a single drug at 10 or 20 mg/m². When myelotoxicity occurred the next therapy cycle was delayed until recovery. RBC indices, hemolysis, erythropoietin, liver and kidney function were studied. MC cycles were 136 (3.6 ± 1.4 per pt), 32 being delayed because of myelotoxicity.Hematocrit, hemoglobin and RBC were inversely related to the cumulative dose (r = 0.70 to 0.86; p 0.03 to 0.01) of MC. Other tests remained stable. Anemia occurred almost twofold earlier in the 20 mg/m² group (p=0.049). basal erythropoietin, already lower than in age and sex watched 81 non cancerous subjects (p<0.001), decreased during MC therapy (p<0.01). For each given MC mg/m² a 0.0372 Hb mg/dl reduction occurred. Chronic anemia due to MC is accompanied by erythropoietin reduction. These results can help in designing chemoradiotherapy.