Cardiotoxicity is a well-recognized, serious adverse effect of thoracic
radiation therapy. This study aimed to evaluate longitudinal electrocardiogram (ECG) changes in patients receiving thoracic
radiation therapy and identify correlating factors that can predict the risk of
cardiotoxicity. This retrospective study included 202 patients treated with thoracic
radiation therapy, and
chemotherapy and targeted
therapy were allowed. Mean heart dose (MHD) was evaluated on dose-volume histograms. ECG, high-sensitivity cardiac
troponin T (hs-cTnT), and N-terminal
B-type natriuretic peptide (
NT-proBNP) analyses were conducted before irradiation and during the follow-up period of 6-12 months (average 8 months). Chi square test and logistic regression analysis were applied to identify risk factors associated with ECG changes. At a median time of 3 months postirradiation, 46.5% of patients showed ECG changes, and 33.0% of patients achieved baseline ECG levels during the follow-up period at a median of 5 months postirradiation. Logistic regression analysis identified MHD, hs-cTnT and NT-pro BNP as significant factors associated with ECG changes (P < 0.05). Hs-cTnT and
NT-proBNP were increased significantly after
radiation therapy compared with baseline levels (P < 0.05), and these increases were observed as a median time of 2 months postirradiation, which was earlier than ECG changes. Higher MHD and elevated hs-cTnT and
NT-proBNP levels correlated with an increased risk of ECG changes in patients receiving thoracic
radiation therapy. Early identification of patients at high risk of
cardiotoxicity and timely intervention might reduce the incidence of radiation-induced
cardiac toxicity.