Smoking, preexisting heart disease, tumor proximity to the heart, and high radiotherapy dose are associated with radiation-induced heart disease after IMRT

Objectives: To identify factors associated with radiation-induced heart disease (RIHD) after intensity-modulated radiotherapy (IMRT) for non-cardiac malignancies and assess the value of combined dynamic electrocardiography (DCG), cardiac troponin I (cTnI), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) monitoring.Methods: This retrospective study included 160 patients who underwent IMRT between January 2024 and January 2025 and completed 12 months of follow-up.Patients were classified into RIHD (n=50) and control (n=110) groups.DCG and cardiac biomarkers were assessed before radiotherapy and at 3, 6, and 12 months.Multivariable logistic regression identified factors associated with RIHD.Results: RIHD occurred in 31.25% of patients.Smoking (OR=3.42,95% CI: 1.55-7.55,P=0.002), previous heart disease (OR=3.68,95% CI: 1.72-7.90,P=0.001), tumor location near the heart (OR=2.16,95% CI: 1.05-4.45,P=0.036), and radiotherapy dose ≥55 Gy (OR=2.57,95% CI: 1.08-6.11,P=0.033) were independently associated with RIHD, whereas surgery was associated with lower odds (OR=0.43,95% CI: 0.21-0.88,P=0.021).cTnI and NT-proBNP were higher in the RIHD group at all post-radiotherapy assessments (all P<0.001), whereas conventional myocardial enzymes did not differ.Among RIHD patients, DCG abnormalities increased from 14.00% at baseline to 68.00% at 12 months (Q=54.692,P<0.001).Combined DCG/ cTnI/NT-proBNP assessment yielded a 92.00% positive detection rate versus 78.00% for DCG and 72.00% for biomarkers alone (adjusted P=0.023 and 0.004).Conclusions: Baseline cardiovascular risk, tumor proximity to the heart, and higher radiotherapy dose were associated with RIHD.Combined longitudinal monitoring may increase abnormal-signal detection among confirmed RIHD cases, although its diagnostic performance requires validation.