High-dose thoracic radiotherapy (RT) tended to cause cardiac events that were independently linked with heart dose and baseline cardiac risk in a study involving 112 individuals with non-small cell lung cancer (NSCLC).

Participants received dose-escalated RT to a median of 74 Gy. Investigators reviewed RT plans and cardiac doses, looking for pericardial effusion, acute coronary syndrome, pericarditis, significant arrhythmia, and heart failure. Among the results:

• ~One-fourth of patients had 1 or more events; the first event occurred at a median of 26 months.

• Heart doses, coronary artery disease, and WHO/International Society of Hypertension score were linked with cardiac events.
• Heart doses remained significant after multivariable analysis.
• 2-year competing risk–adjusted event rate for patients with heart average dose <10 Gy was 4%.
• The rate was 7% in patients with average dose of 10 to 20 Gy, and 21% in those whose mean dose was ≥20 Gy.
• Heart doses were not linked with overall survival.