Myocardial infarction secondary to 5-fluorouracil: Not an absolute contraindication to rechallenge?

Abstract

5-fluorouracil (5-FU) is one of the most commonly prescribed che-motherapeutic agents for the treatment of a variety of malignancies.5-FUcardiotoxicityisuncommonbutpotentiallyserious:includingcar-diac arrhythmias, angina/myocardial infarction, ventricular dysfunction,cardiogenic shock, cardiac arrest, and sudden cardiac death [1].Anesti-mated 2–10% of patients exposed to 5-FU will develop cardiovascularcomplications; and patients with known ischaemic heart disease orprior myocardial infarction appear to be at higher risk [2].Proposedmechanismsunderlying5-FUcardiotoxicityincludedirectmyocardial toxicity, thrombogenic effects, immune phenomena andmyocardial ischaemia secondary to coronary artery vasospasm [3].Whilstrechallengewith5-FUisnotgenerallyrecommendedinpatientswith 5-FU cardiotoxicity due to concerns regarding recurrence anddeath: a careful assessment of the risks and benefits of such a rechal-lenge should be carefully conducted [3]. At present no consensus onprophylaxisortreatmentof5-FUcardiotoxicityexists,anddiscontinua-tion of 5-FU with the use of second-line agents is generally preferred.Adjuvant therapy with 5-FU containing chemotherapeutic regimensforms the basis of colon cancer therapy, carrying significant long termbenefits to both recurrence free and overall survival. These benefitsare not insignificant, with reductions in recurrence free and overallsurvival of 40% and 33% respectively, when compared to observationalone [4]. Furthermore, these benefits also remain superior to that ofalternativeagents,suchasRaltitrexed[5].Wedescribethefirstreportedcase of successful 5-FU rechallenge underclosecardiacobservation in apatient with 5-FU induced vasospastic myocardial infarction.A previously well 30 year old male with resected stage III (T4a,N2a) colorectal adenocarcinoma was commenced on 5-FU,leucovorin and oxaliplatin (FOLFOX 6) adjuvant chemotherapy(5- fluorouracil 400 mg/m