Routine assessment of cardiotoxicity in patients undergoing long-term immune checkpoint inhibitor therapy

The indications for immune checkpoint inhibitors (ICIs) are expanding in cancer drug therapy, and while cardiac events associated with ICIs are often fatal, there are few reports regarding cardiac complications associated with long-term ICI therapy. We aimed to study cardiac complications in patients undergoing long-term ICI therapy. From the database of our local cardio-oncology unit, we enrolled patients with cancer undergoing ICI therapy for more than 6 months and for whom cardiologists continuously performed routine follow-ups. We defined the primary endpoint as discontinuation of ICI due to cardiac events. We also analyzed changes in cardiac biomarkers and echocardiographic parameters. We retrospectively analyzed 55 consecutive patients (43 males, mean age: 65 ± 11 years) treated with ICI therapy in our hospital between January 2017 and June 2021. None of the patients discontinued ICI therapy due to cardiac events more than 6 months after treatment was initiated. Among the participants, we observed four patients with elevated serum troponin I levels, seven patients with decreased global longitudinal strain values, and two patients with elevated plasma brain natriuretic peptide levels. No patient required drug intervention for these cardiac events; furthermore, there were no cases of clinically diagnosed myocarditis. In the present study, there were no cardiac events causing ICI discontinuation in patients undergo ICI therapy for more than 6 months.