Subclinical cardiotoxicity following adjuvant dose-escalated FEC, high-dose chemotherapy, or CMF in breast cancer

We compared adjuvant chemotherapy-related myocardial damage by antimyosin scintigraphy in patients who received either nine cycles of FEC (fluorouracil, epirubicin and cyclophosphamide) where the doses of epirubicin and cyclophosphamide were escalated according to the leucocyte nadir (group I, n = 14), three cycles of FEC followed by high-dose chemotherapy with alkylating agents (CTCb) given with the support of peripheral blood stem cell transplantation (group II, n = 14), or six cycles of standard intravenous CMF (cyclophosphamide, methotrexate and fluorouracil; group III, n = 8). The cardiac uptake of In-111-antimyosin-Fab (R11D10) antibody was measured and the heart-to-lung ratio (HLR) calculated 8-36 months after the last dose of chemotherapy. Cardiac antimyosin antibody uptake was considerably higher among patients treated with nine cycles of dose-escalated FEC than among those who were treated with three cycles of FEC and high-dose CTCb (HLR, median 1.98; range 1.36-2.24 vs median 1.51; range 1.20-1.82; P < 0.001), or those treated with CMF (median 1.44; range 1.15-1.68; P < 0.001). The difference between groups II and III was not significant (P > 0.1). A linear association was found between the cumulative dose of epirubicin and the cardiac antimyosin uptake (P < 0.001). We conclude that subclinical cardiac damage caused by three cycles of conventional-dose FEC followed by one cycle of high-dose CTCb chemotherapy is small as compared with the damage caused by dose-escalated FEC.