High prevalence of coronary artery calcification on routine chest CT in cancer survivors with radiotherapy-associated valvular disease

Background Thoracic radiotherapy (RT) can cause late radiation-associated cardiac disease including valvular heart disease and coronary artery disease. The burden of concomitant coronary artery calcification (CAC) in survivors with post-RT valvular disease is insufficiently characterised. Purpose To quantify CAC on routine chest computed tomography (CT) in cancer survivors with echocardiographically verified valvular disease after RT, and to explore associations with breast RT laterality, age and time since RT. Methods Single-centre retrospective cohort study (2012–2023) from a cardio-oncology registry. Inclusion required prior thoracic/mediastinal RT, ≥1 valvular abnormality on echocardiography, and an available non-contrast CT. CAC was scored on non-ECG-gated CT using a validated ordinal method: each coronary artery (left main [LM], left anterior descending [LAD], left circumflex [LCx], right coronary artery [RCA]) was graded 0–3 by calcification extent; the summed score (0–12) was categorised as none (0), mild (1–3), moderate (4–6) or severe (7–12). Prevalence was reported with 95% confidence intervals (CI). Fisher’s exact test compared CAC prevalence after left- versus right-sided breast RT. Binomial logistic regression assessed associations of age and years since RT with any CAC. Results Of 62 registry patients, 44 met inclusion criteria (61.4% female; mean age 65.2±12.4 years). Mean time since RT was 19.6±12.7 years. Indications for RT were breast cancer 34.1% (left-sided 25.0%, right-sided 9.1%) and lymphoma 31.8%. Common valvular lesions were mitral regurgitation 59.1%, aortic stenosis 50.0% and aortic regurgitation 36.4%. Median CAC score was 4 (interquartile range 0–9). Any CAC was present in 72.7% (32/44; 95% CI 57.2–85.0); moderate/severe CAC in 50.0% (22/44; 95% CI 34.6–65.4); severe CAC in 41.0% (18/44). LAD had the highest vessel burden (mean 1.55±1.23); median number of affected vessels was 3/4 (interquartile range 0–4). Among breast cancer survivors (n=15), CAC was present in 81.8% (9/11) after left-sided vs 50.0% (2/4) after right-sided RT (p=0.516; OR 4.5, 95% CI 0.37–54.2). In logistic regression (Nagelkerke R2=0.237), years since RT was associated with CAC (OR per year 1.072, 95% CI 1.001–1.149; p=0.046), whereas age was not (p=0.091). Conclusion(s) Cancer survivors with RT-associated valvular disease frequently have multi-vessel CAC on routine CT, with half demonstrating moderate-to-severe burden. Opportunistic CAC assessment on existing chest CT may improve risk stratification and support intensified prevention and/or coronary evaluation when managing radiation-associated valvular disease.