Cardiotoxicity of Chemoradiotherapy in Patients With Esophageal Cancer: A Systematic Review

Concurrent chemoradiotherapy (CRT) remains a standard treatment for locally advanced esophageal cancer, yet the approach poses significant cardiotoxic risks due to the proximity of the esophagus to cardiac structures. This systematic review synthesized recent evidence from observational studies and systematic/narrative reviews published in the last five years, with a focus on quantifying the incidence and timing of cardiac events, examining mechanisms of CRT-induced cardiotoxicity, and evaluating strategies for monitoring and mitigating cardiac risk.  A comprehensive search was conducted in PubMed, PubMed Central, Cochrane Library, Google Scholar, and ScienceDirect, restricted to English-language studies published within the past five years, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Eligible studies specifically investigated CRT in esophageal cancer patients and reported cardiac outcomes. Cardiotoxicity is defined as acute (≤90 days), subacute (3-6 months), or chronic (>6 months) outcomes, including pericardial effusion, arrhythmias, ischemic events, myocardial fibrosis, and heart failure, assessed through imaging, biomarkers, or clinical endpoints.  Findings showed that acute events such as pericardial effusion and arrhythmias occur frequently within 90 days post-CRT, while chronic conditions, including ischemic heart disease and heart failure, are more prevalent among long-term survivors. Older patients and those with pre-existing cardiovascular disease were particularly vulnerable to CRT-related cardiac injury.  CRT for esophageal cancer carries substantial acute and chronic cardiotoxic risks. Mechanisms involve radiation-induced fibrosis and endothelial injury, compounded by chemotherapy-associated oxidative stress and vasospasm. Clinical implications include the adoption of heart-sparing radiotherapy techniques, systematic biomarker monitoring (BNP, troponin), and cardioprotective agents such as beta-blockers or ACE inhibitors. Advanced imaging (cardiac MRI, echocardiography) offers opportunities for early detection of subclinical injury. Future research should prioritize standardized dosimetry for cardiac substructures (e.g., mean heart dose, LAD constraints) and prospective studies integrating biomarker- and imaging-based cardiac assessment tools to better balance oncologic efficacy with cardioprotection, ultimately improving survival and quality of life in this high-risk patient population.