DETECTION OF DOXORUBICIN CARDIOTOXICITY IN PATIENTS WITH SARCOMAS BY INDIUM-111-ANTIMYOSIN MONOCLONAL-ANTIBODY STUDIES

To assess myocardial cell damage due to doxorubicin cardiotoxicity, we prospectively studied 30 patients with sarcomas who were receiving ch emotherapy, including doxorubicin. Sixteen patients were treated by co ntinuous infusion over 72 hr and 14 patients were treated by bolus inj ection. Antimyosin studies and left ventricular ejection fraction (LVE F) measurements were performed before chemotherapy and at intermediate and maximal cumulative doses. Myocardial antimyosin uptake was quanti fied by a heart-to-lung ratio (HLR). Myocardial antimyosin uptake was observed in all patients at 240-300 mg/m2 when ejection fraction was s till maintained. Seven patients presented with a decrease of greater-t han-or-equal-to 10% in absolute ejection fraction units at 420-600 mg/ m2. Five of these patients had mild congestive heart failure. All pati ents who presented with a decrease in LVEF greater-than-or-equal-to 10 % at 420-600 mg/m2 had increased antimyosin uptake with HLR greater-th an-or-equal-to 1.90 at a cumulative dose of 240-300 mg/m2. Patients wh o were treated with continuous infusion had less antimyosin uptake tha n those who were treated with bolus administration (mean HLR of 1.70 /- 0.09 versus HLR of 2.01 +/- 0.16 at a cumulative dose of 240-300 mg /m2, p < 0.01; HLR of 1.86 +/- 0.12 versus HLR of 2.32 +/- 0.34 at a c umulative dose of 420-600 mg/m2, p < 0.01). Two of 16 patients treated by continuous infusion and 5 of 14 patients treated by bolus injectio n presented with a decrease in ejection fraction greater-than-or-equal -to 10%. LVEF after chemotherapy in the infusion group was 56% +/- 5% and 48% +/- 8% (p < 0.05) in the bolus group. Antimyosin studies are h elpful in the assessment of doxorubicin cardiotoxicity. Intense antimy osin uptake at intermediate cumulative doses identifies patients at ri sk of cardiotoxicity before ejection fraction deteriorates. Patients w ith sarcomas treated by continuous infusion present with less antimyos in uptake than those treated with bolus injection, indicating less sev ere cardiotoxicity.