Impact of Radiation Therapy for Breast Cancer on the Coronary Artery Disease Profile at Cardiac CT

Purpose To evaluate the coronary artery disease (CAD) profile and valvular and structural alterations seen at coronary CT angiography (CTA) after radiation therapy (RT) for breast cancer in a case-control study. Materials and Methods Patients who underwent clinically indicated coronary CTA were included in this retrospective study. The following parameters were evaluated: coronary artery calcium (CAC) score, Coronary Artery Disease Reporting and Data System (CAD-RADS) score, high-risk plaque (HRP) phenotypes, and extracoronary findings (valvular fibrosis, fibrous adherence). Patients with breast cancer who underwent RT were propensity score-matched with controls (level: <i>P</i> = .05) for age, body mass index, and major cardiovascular risk factors to reduce selection bias and confounding. Results Among 154 female patients (mean age, 65.23 years ± 10.4 [SD]; 77 patients in RT group, 77 patients in control group), there was no evidence of a difference in CAC score between the RT and control groups (201.1 vs 75.4 Agatston units [AU], <i>P</i> = .64). No difference was seen in coronary stenosis severity (CAD-RADS score) (<i>P</i> = .40) or obstructive disease (>50% stenosis) rate (29% [22 of 77] vs 23% [18 of 77], <i>P</i> = .46; odds ratio [OR], 1.31 [95% CI: 0.63, 2.73]). No between-group difference was observed in high-risk plaque phenotype rate (9% [seven of 77] vs 17% [13 of 77], <i>P</i> = .23) or CAC or CAD-RADS scores. There was no evidence of a difference between left versus right RT for CAC (309 vs 120 AU, <i>P</i> = .23), coronary stenosis severity (CAD-RADS score, <i>P</i> = .43), or HRP phenotype rate (left, 11% [four of 36]; right, 6% [two of 34]). The prevalences of valvular fibrosis and calcifications were low (5% [four of 77] vs 3% [two of 77] [<i>P</i> = .68] and 16% [12 of 77] vs 9% [seven of 77] [<i>P</i> = .37], respectively; OR, 1.84 [95% CI: 0.68, 5.25]). The prevalence of fibrous adherence of the left anterior descending coronary artery or right coronary artery to the chambers was 1.4-fold higher in the RT group (29% [22 of 77] vs 13% [17 of 77] [<i>P</i> = .46]; OR, 1.41 [95% CI: 0.68, 2.97]). Conclusion RT for breast cancer was not associated with more severe coronary stenosis, HRP phenotypes, or valvular fibrosis in this case-control population cohort. <b>Keywords:</b> Coronary Arteries, Radiation Effects, CT-Coronary Angiography, Cardiac, Breast, Breast Cancer, Radiation Therapy, Cardiovascular Risk, Computed Tomography, Coronary Artery Disease <i>Supplemental material is available for this article.</i> © RSNA, 2026.