High sensitivity of radiolabelled antimyosin scintigraphy in assessing anthracycline related early myocyte damage preceding cardiac dysfunction.

In antimyosin scintigraphy was evaluated at various cumulative anthracycline dose levels in order to early identify patients with severe cardiac injury and increased long-term risk of cardiac dysfunction. Twenty-four patients receiving standard doses of 60-75 mg.m(-2) doxorubicin or 90-112.5 mg.m(-2) epirubicin were followed at baseline, low (two cycles), middle (four cycles), and high (six cycles) cumulative dose using (111)In antimyosin 48 h heart-to-lung ratio (HLR), left ventricle ejection fraction (LVEF) and peak filling rate (PFR). At a low cumulative dose only HLR was significantly increased (P=0.0001); at middle dose HLR (P<0.0001) and LVEF (P=0.0054), but not PFR, were significantly changed, and at high dose HLR (P<0.0001), LVEF (P=0.0001) and PFR (P=0.033) all changed significantly. Concerning individual results, HLR became abnormal in 18 patients (75%) at low, 22 (92%) at middle, and 24 (100%) at high cumulative dose whereas LVEF and PFR remained within normal limits in all patients. It is concluded that myocyte damage appears to precede left ventricle systolic and diastolic dysfunction in anthracycline treatment. (111)In antimyosin scintigraphy is very sensitive in detecting myocardial damage after cumulative dose levels even as low as 120-150 mg.m(-2) doxorubicin or 180-225 mg.m(-2) epirubicin.