Electrocardiographic abnormalities in childhood cancer survivors treated with cardiotoxic therapy: a systematic review

PURPOSE: The purpose of this study is to assess the available literature on the prevalence and risk factors of electrocardiographic (ECG) abnormalities after cardiotoxic treatment in childhood cancer survivors (CCS).

METHODS: A literature search was performed within MEDLINE, EMBASE, and CENTRAL (1966-11/2020) and reference lists of relevant studies. Studies were eligible for inclusion if they reported ECG abnormalities ≥2 years after cancer diagnosis in ≥50 CCS treated with anthracyclines, RT involving the heart region and/or mitoxantrone. Information about population, treatment, outcome, and risk factors were extracted and risk of bias was assessed.

RESULTS: Of 934 identified publications, 10 studies were included. Outcome definitions, treatment regimens, follow-up period, and risk of bias varied. These ECG abnormalities and prevalences were reported: major (5%-23%) and minor (12%) abnormalities according to the Minnesota Code, rhythm abnormalities (0%-12%), conduction abnormalities (0.3%-7.1%), depolarization abnormalities (0%), and repolarization abnormalities (0%-65%). The reported risk factors of ECG abnormalities (two studies) are male sex, anthracyclines, RT involving the heart region, and hypertension, although results were not univocal between studies and abnormalities.

CONCLUSIONS: Multiple ECG abnormalities have been described in CCS ≥2 years from diagnosis, some of which can have important implications. Future research is needed to evaluate the exact long-term incidence and risk factors, and to investigate their clinical relevance and relation with cardiac dysfunction or future cardiac events. This could improve cardiac surveillance for CCS.