Cardiac substructures dosimetric predicts cardiac toxicity and prognosis in esophageal squamous cell cancer treated by radiotherapy

Purpose: To look into the relationship between cardiac substructures (CS) dosimetric parameters and cardiac events (CE) or overall survival (OS) in patients undergoing radiation therapy (RT) for esophageal squamous cell carcinoma (ESCC). Methods and materials: A retrospective study included 350 patients with ESCC receiving definitive chemoradiotherapy or radiotherapy (d-CRT/d-RT) or neoadjuvant chemoradiotherapy (NCRT) from March 2013 to May 2022. Our study examined the adverse cardiac events of any grade or G3+, as defined by the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Competing risk analysis and Cox regression analysis were used to assess the relationship between CS doses and CEs or OS. Results: 201 (57.4 %) patients received any grade CEs over a median follow-up time of 22.50 months (IQR, 12.40-45.60), and 24 (6.86 %) patients suffered G3+ CEs. On landmark analysis, patients with any grade CEs had significantly lower OS (P = 0.003). Multivariable analysis revealed that any grade CEs were predicted by the dose of CSs in all populations. In addition, for G3+ cardiac events, arrhythmic and small probability of cardiac events, LAD V20 ((HR: 1.02, 95 % CI: 1.00-1.03, P = 0.012; HR: 1.01, 95 % CI: 1.00-1.02, P = 0.005; HR; 1.01, 95 % CI: 1.00-1.02, P = 0.012) was also an independent predictive factor. LAD V50 (HR: 1.07, 95 % CI: 1.03-1.10, P <0.001) predicted pericardium effusion events. Moreover, the multivariable analysis revealed that OS was predicted by LAD V30 (HR: 1.03; 95 % CI, 1.01-1.05, P = 0.015). Conclusions: In the population of ESCC patients receiving RT, we showed that the CS factors had a substantial predictive value for the various types and grades of CEs. The elevated radiation dose of LAD was a significant contributor to a higher rate of cardiac events and a worse prognosis.