Cardiac Substructure Analysis of Radiation-associated Cardiac Disease in Thoracic Malignancy Patients

Radiation-associated cardiac disease frequently affects cancer patients when radiation fields overlap the heart, but relationships between cardiac substructure dose and specific cardiac events remain poorly understood. This study examined associations between radiation dose to cardiac substructures and adverse cardiac events in thoracic malignancy patients. We retrospectively analyzed 94 patients with lung, esophageal and breast cancers who received radiation therapy. Radiation-induced adverse cardiac events included pericardial disease, atrial fibrillation/flutter, heart failure and valve disease. We evaluated associations between cardiac substructure radiation doses and adverse event types. Results showed that increasing radiation doses to the pericardium, left atrium and whole heart were associated with higher odds of pericardial disease. Median onset times varied: 7 months for pericardial disease, 10 months for atrial fibrillation/flutter and 16 months for heart failure. Clear associations emerged between specific cardiac substructure radiation doses and corresponding adverse event types. Sex-specific differences in cardiac substructure radiation dose were also identified. These findings demonstrate important relationships between cardiac substructure radiation exposure and specific adverse events in patients receiving thoracic radiation therapy. The results underscore the critical importance of considering both cardiac substructure dose distributions and patient sex when developing strategies to mitigate treatment-related cardiac risks in cancer patients.