Heart Substructure Radiation Dose and Cardiac Outcomes: Contemporary Evidence and Actionable Opportunities (JACC: CardioOncology State-of-the-Art Review June 2026)-Article: Heart Substructure Radiation Dose and Cardiac Outcomes: Contemporary Evidence and Actionable Opportunities

Pdf Summary

This state-of-the-art review argues that cardiac radiation risk is better understood through <strong>specific heart substructures</strong> than through whole-heart dose alone. Contemporary evidence links <strong>coronary artery dose</strong> most strongly with ischemic events and major adverse cardiac events, <strong>left ventricular/myocardial dose</strong> with heart failure and subclinical dysfunction, and <strong>pulmonary vein/left atrial dose</strong> with atrial fibrillation and other arrhythmias. Other regions, including valves, pericardium, heart base, and pulmonary artery, are also relevant to distinct outcomes.

The authors emphasize that the current evidence base is rich but inconsistent, and that clinical guidelines have not fully translated these findings into practical dose thresholds or surveillance pathways. Most society statements and NCCN disease-site guidelines still rely mainly on broad terms like “high-dose chest RT” or whole-heart metrics such as mean heart dose, with Hodgkin lymphoma being a major exception.

To close this evidence-to-practice gap, the review proposes a <strong>three-pillar framework</strong>:
1. <strong>Assess baseline cardiovascular risk</strong> using traditional risk factors and opportunistic markers such as coronary artery calcium on planning CT.
2. <strong>Use high-value substructure dosimetry</strong>, especially for the left coronary arteries and left ventricle, and interpret dose in relation to likely cardiac endpoints.
3. <strong>Apply actionable risk-reduction strategies</strong>, including auto-segmentation, selective contouring, practical dose constraints, and communication of dose exposure to cardiology and primary care teams.

The review also offers pragmatic planning goals, such as prioritizing left coronary artery sparing when feasible, while recognizing that tumor coverage remains the priority. Overall, it concludes that there is no universally “safe” heart dose, and that intentional, evidence-informed substructure sparing is now an important opportunity to reduce radiation-associated cardiac harm.

Meta Tag

Concept Cardiac Radiation Dose

Concept Cardiovascular Outcomes

Concept Cardiac Substructure Dose

Concept Myocardial Ischemia

Concept Heart Failure

Keywords

cardiac radiation risk

heart substructures

coronary artery dose

left ventricular dose

myocardial dose

pulmonary vein dose

left atrial dose

atrial fibrillation

mean heart dose

substructure dosimetry

Cardiac Radiation Dose

Cardiovascular Outcomes

Cardiac Substructure Dose

Myocardial Ischemia

Heart Failure