Prevention of 5 fluorouracil associated cardiotoxicity

5-Fluorouracil induces arterial vasoconstrictions but does not increase angiotensin II levels

Because the mechanisms of 5-Fluorouracil (5-FU) cardiotoxicity have not yet been completely identified, prophylactic options are not available. To our knowledge, there are no published data investigating the use of angiotensin converting enzyme (ACE) inhibitors for 5-Fluorouracil-associated cardiotoxicity. In this study, we aimed to evaluate the influence of 5-FU administration on the diameter of the brachial artery and the levels of angiotensin II. The patients were administered bolus 5-FU/leucovorin in the study group. Angiotensin II and troponin T assays, complete blood cell counts, hepatic and renal function tests were analyzed in five consecutive blood samples in the initiation, just after termination, and on 24, 48, and 72 h after termination of the regimen. Pre- and post-treatment angiotensin II and troponin T assays, complete blood cell counts, hepatic and renal function tests were also analyzed in the control group. Brachial arterial diameters were measured and recorded in all patients before and after the treatment. A total of 59 patients were included in this study. Thirty one out of 59 patients (52.5%) were in the 5-FU study group and the remaining 28 patients (47.5%) were in the control group. Basal and post-treatment brachial artery diameters in the 5-FU study group were 0.436 +/- 0.51 and 0.423 +/- 0.50 cm, respectively (P = 0.001). The corresponding values in the controls were 0.3954 +/- 0.50 and 0.3957 +/- 0.49 cm, basal and post-treatment, respectively (P = 0.979). Angiotensin II levels were not changed significantly at serial measurements (P = 0.496). Moreover, the corresponding measurements were not statistically different in both two groups treated with and without 5-FU (P = 0.372). The pathophysiology of 5-FU-induced cardiac toxicity has not yet been elucidated. In the present study, 5-FU-associated vasoconstriction was not dependent on angiotensin II levels, thus we suggest that the prophylactic administration of ACE inhibitors cannot prevent cardiotoxicity in these patients. The underlying mechanisms of cardiotoxicity related to 5-FU might be multifactorial; nevertheless, further prospective investigation for the toxic effects of fluoropyrimidines on the coronary endothelium and myocardium are needed.

Cardiotoxicity of the antiproliferative compound fluorouracil

The antimetabolite fluorouracil (5-FU) is frequently administered for chemotherapy of various malignant neoplasms. The drug is well known for its adverse effects involving bone marrow, skin, mucous membranes, intestinal tract and central nervous system, whereas its cardiotoxicity is less familiar to clinicians. The pathophysiology of fluorouracil-associated cardiac adverse events is controversial and conclusions are based on clinical studies and case reports more than on solid experimental evidence. While clinical and electrocardiographic features suggest myocardial ischaemia as a main aetiological factor, possibly induced by coronary vasospasm, histomorphological and biochemical studies indicate a more direct drug-mediated cytotoxic action. Estimates of the overall incidence of fluorouracil cardiotoxicity have varied widely from 1.2 to 18% of patients. Patients may present with angina-like chest pain, cardiac arrhythmias or myocardial infarction. There is no unequivocally effective prophylaxis or treatment in this syndrome. Once fluorouracil administration is discontinued symptoms are usually reversible, although fatal events have been described. The overall mortality rate has been estimated to be between 2.2 and 13.3%. There is a high risk of relapse when patients are re-exposed to this drug following previous cardiac incidents. From the present data it is concluded that cardiotoxicity is a relevant but underestimated problem in fluorouracil treatment. Since the mechanisms of fluorouracil-associated cardiotoxicity are not yet fully understood, all patients undergoing this chemotherapy have to be carefully evaluated and monitored for cardiac risk factors and complaints. After cardiotoxic events, fluorouracil should definitely be withdrawn and replaced by an alternative antiproliferative regimen.