Safe administration of S-1 after 5-fluorouracil-induced cardiotoxicity in a patient with colorectal cancer

Cardiotoxicity is a rare but challenging complication of 5-fluorouracil (5-FU) therapy. Compared with 5-FU, after application of S-1 lower plasma levels of the cardiotoxic metabolite alpha-fluoro-beta-alanine have been reported. Evidence for safe administration of S-1 following 5-FU cardiotoxicity is limited to a case report in an Asian patient. Herein we report the first case of S-1 application after 5-FU cardiotoxicity in a Caucasian patient. A 67-year-old man with right-sided metastatic colorectal cancer and history of 5-FU cardiotoxicity had a progressive disease after 8-month therapy with irinotecan and bevacizumab. In consideration of known 5-FU cardiotoxicity, he was referred to our department for therapy counselling. We started a combination therapy with S-1, oxaliplatin and bevacizumab. The treatment was well tolerated without any cardiac problems. Our report confirms the safety of S-1 in cases of 5-FU cardiotoxicity also in a Caucasian patient.