[Cardiotoxicity of 5-fluorouracil]

To determine the possibility and magnitude of cardiotoxicity following high dose intravenous infusion of fluorouracil (5-FU).

A prospective clinical study was performed on 104 patients with choriocarcinoma and invasive mole. 5-FU was administered by slow intravenous infusion in 5% glucose 500 ml for 8 hours at doses of 28-30 mg.kg-1.day-1 when used as a single agent treatment or 24-26 mg.kg-1.day-1 when used in combination with kengshengmycin (KSM). The total cycles of treatment with 5-FU + KSM were 109 and those of 5-FU or KSM each used as a single agent were 71 and 12 respectively. The cardiac functions were monitored by cardiac symptoms, ECG and serum cardiac enzymes before and after 5-FU infusion.

Among the 192 treatment cycles tachycardia, palpitation or cardiac distress were observed in 14 cycles. ECG showed changes of ST or T waves in 8 cycles, sinus tachycardia in 3 cycles. The results of serum cardiac enzyme determinations were variable. The diagnostic criteria of cardiotoxicity were appearances of abnormalities manifested in any two of the three monitor items. The incidence of cardiotoxicity was 4.2% in 5-FU group, 4.6% in 5-FU + KSM group and 0% in KSM group. All episodes were mild, reversible spontaneously after cessation of chemotherapy and did not reappear in subsequent chemotherapeutic cycles. Seven patients with definite cardiac diseases before chemotherapy were given 5-FU treatment, but no obvious aggravation of cardiotoxicities were observed even with repeated 5-FU treatments.

Only occasional cardiotoxicities were observed in 5-FU treatments. They were rather mild and reversible. The incidence of cardiotoxicity might be reduced with emphasis on strict observance of the treatment regimen in regard to the dosage used, the speed of the infusion and attention to the treatment of any side-effects.