Evaluation of cardiotoxicity of a combined bolus plus infusional 5-fluorouracil/folinic acid treatment by echocardiography, plasma troponin I level, QT interval and dispersion in patients with gastrointestinal system cancers.
OBJECTIVE: To evaluate the cardiotoxicity of LV5FU2 regimen (bolus plus infusional 5-fluorouracil/folinic acid) treatment by non-invasive methods such as echocardiography, plasma troponin I (TnI) level, QT interval and QT dispersion on ECG. METHODS: Twenty-two patients with gastrointestinal cancer who received LV5FU2 chemotherapy were evaluated prospectively during 12 cycles of chemotherapy. Plasma TnI assay and ECG recording analyses were performed before the first cycle, at 24 h, before each cycle until cycle 6 and every three cycles thereafter. The longest QT interval measurement on each recording corrected with Bazzett's formula was considered as QTmax and the difference between the QTmax and the shortest corrected QT interval was considered as QT dispersion (QTd). A complete M-mode, 2D and color Doppler echocardiogram was performed at baseline and at the first, third and sixth months of treatment. RESULTS: Echocardiography did not show any significant change in either systolic or diastolic functions. Also, TnI measurements were found to be below detectable level in all patients and in all measurements. Meanwhile, significant prolongations of QTmax and QTd were observed as early as 24 h after first administration of chemotherapy. These events persisted and became more important over the duration of chemotherapy (P < 0.05). CONCLUSIONS: The clinical implication of these findings as predictive factors for subsequent events such as malignant arrhythmias in patients taking 5-fluorouracil-based chemotherapy need longer follow-up and further detailed evaluations.