Cardiac Substructure Dose Response after Lung Cancer Radiotherapy

Area of Science:

• Oncology
• Radiotherapy
• Cardiology

Background:

• Lung cancer radiation therapy poses cardiac risks due to the heart's proximity to the lungs.
• Current planning minimizes whole heart radiation dose, but emerging evidence suggests substructure doses are more predictive of cardiac events.

Purpose of the Study:

• To review and consolidate findings on cardiac substructure radiation doses and their association with adverse cardiac outcomes.
• To inform lung radiotherapy planning and establish dose thresholds for specific cardiac substructures, especially in high-risk patients.

Main Methods:

• Systematic review of 32 studies published between 2017 and 2024, identified via PubMed searches.
• Analysis of correlations between radiation doses to specific cardiac substructures and postradiotherapy cardiac events.

Main Results:

• Radiation doses to heart chambers, conduction nodes, great vessels, coronary arteries, pericardium, and valves are linked to adverse outcomes.
• Minimizing dose to the left ventricle, left atrium, heart base, and left coronary arteries (LAD, LCx) is recommended.

Conclusions:

• Individual cardiac substructure doses are more accurate predictors of cardiac risk than whole heart dose alone.
• Utilizing substructure dose constraints in lung radiotherapy planning can enhance long-term patient outcomes and well-being.