Feasibility of Switching Fluoropyrimidine Due to Cardiotoxicity in Patients with Solid Tumors: a Retrospective, International and Non-interventional Study

Fluoropyrimidine chemotherapy agents, such as 5-fluorouracil and capecitabine, are occasionally associated with cardiotoxicity that may manifest as chest pain, ECG alterations, cardiac arrhythmia, and rarely myocardial infarction and sudden death. Clinical fluoropyrimidine cardiotoxicity is infrequent (1-8% of patients), but subclinical toxicity may be much more common (up to one third of patients). The underlying mechanisms are not well understood, but they may include abnormal coronary artery contractility or spasm, and myocardial toxicity. Cardiotoxicity may be less frequent with S-1 (a combination of tegafur, gimeracil and oteracil at a molar ratio of 1:0.4:1) as compared with 5-fluorouracil and capecitabine, but head-to-head comparisons are lacking.

Anecdotal evidence suggests that patients who have cardiotoxicity on other fluoropyrimidines may be successfully treated with S-1. The purpose of this retrospective study is to compare different 5-fluorouracil-based dosing modalities and S-1, and compare cardiotoxicity during these treatments.

The patient population was treated for solid tumors with a 5-fluorouracil based regimen and had a cardiac event grade 1-4. All patients were re-challenged with a different fluoropyrimidine or S-1 and assessed for cardiotoxicity during re-challenge.