Troponin T and myoglobin for monitoring cardiotoxicity of weekly epirubicin-paclitaxel (EP) in advanced breast cancer (ABC) patients

Proc Amer Assoc Cancer Res, Volume 46, 2005 3994 Background: Troponin T (TnT) and myoglobin (M) have been described to predict the anthracycline-induced cardiac injury. In fact, increasing serum level of TnT has been recently reported to be related to cumulative antracyclines exposure. Left ventricular ejection fraction (LFEV) seems accurate in monitoring systolic function for cardiac damage measurement and its decrease has recently included among the parameters of toxicity criteria by chemotherapeutics (CTC 3.0). E/A ratio is useful to assay diastolic function to predict systolic failure. Methods: From January 2002, 20 patients with untreated ABC received E (25 mg/m2/week) and P (80 mg/m2/week) with G-CSF support on days 2 and 4 for 24 consecutive weeks. We measured TnT, M, alanine transaminase (ALT), aspartate transaminase (AST), lactic dehydrogenase (LDH), creatine phosphokinase (CPK), creatine kinase MB (CK-MB), C-reactive protein (CRP) circulating levels immediately before and 4 hours after E administration every week. Patients underwent EKG and echocardiography (Eco) (LFEV and E/A ratio measurement) at week 0, 8, 16 and 24. Results: The number of courses administered was 352 (median 18, range 4-24). E median dose given was 550 mg/m2 (range 100-600) with a median dose intensity (DI) of 22.95 (range 15,6-25) mg/m2/week (91,8%). P median dose administered was 1760 mg/m2 with a median DI of 73.45 (range 50-80) mg/m2/week (91,8%). TnT never overcame the upper normal limit (UNL); 1 patient experienced TnT elevation without any clinical or instrumental sign of cardiac failure. M never significantly increased with the exception of a patient who underwent several abdominal fluid drainages. CK-MB and CRP never moved outside UNL. ALT, AST, LDH were always within the normal range except for patients with liver metastases. No symptomatic cardiac event was recorded. Neither LFEV nor E/A significant decrease was registered. In 55 echocardiograms at week 0, 8, 16, 24, median LFEV and median E/A were respectively: 66%, 67%, 64,5%, 65,5% and 1.1, 1.11, 1,015, 1,1. Conclusions: No TnT or M serum elevations and LFEV/E/A changes were registered in our series of ABC non-symptomatic women during weekly chemotherapy with EP. No acute cardiac toxicity was observed. However, longer follow-up is needed to understand whether the TnT or M circulating level measurement is able to detect subclinical, early stage doxorubicin-induced cardiotoxicity.