Key result
IMPT linked to ~5% lower estimated acute coronary event risk vs IMRT.
Why the study?
Data comparing cardiac substructure doses and toxicity risks between IMPT and IMRT in breast cancer are limited, despite IMPT reducing mean heart dose.
Does IMPT reduce cardiac substructure dose and modeled acute coronary event risk compared to IMRT in breast cancer patients?
Observational (n=30)
Does IMPT reduce cardiac substructure dose and modeled acute coronary event risk compared to IMRT in breast cancer patients?
IMPT significantly reduces radiation dose to cardiac substructures and modeled risk of acute coronary events compared to IMRT in breast cancer patients, particularly those receiving left-sided internal mammary node irradiation.
IMPT may reduce modeled coronary risk via lower cardiac doses in breast RT; leaves open whether events decline versus IMRT.
Background and purpose Intensity-modulated proton therapy (IMPT) significantly reduces mean heart dose (MHD), but data on cardiac substructure dose and toxicity compared to intensity-modulated radiotherapy (IMRT) are limited. This study evaluated dose reduction in cardiac substructures between IMPT and IMRT and assessed cardiac toxicity risks using two Normal Tissue Complication Probability (NTCP) models. Materials and methods A retrospective analysis was conducted on 30 breast cancer patients from a randomized trial with the highest MHD receiving IMRT. IMPT plans were created for a prescribed dose of 4005 cGy(RBE) in 15 fractions. NTCP models by Darby et al. and Bogaard et al. were used to compare individual acute coronary events (ACE) risk between IMPT and IMRT. Results IMPT reduced cardiac substructure doses by 63.34% to 100%, with greater absolute reductions in left-sided and relative reductions in right-sided patients. For left-sided internal mammary node irradiation (IMNI), IMPT achieved an 82.25% reduction for LAD (P = 0.009), 79.45% for RV (P < 0.001), and over 90% for other substructures. Right-sided patients had near-zero mean doses in most substructures. The Darby model indicates IMPT reduces individual ACE risk by 1.58% to 5.16% for left-sided IMNI (P = 0.001) and 0.59% to 1.05% for right-sided IMNI (P = 0.063). The Bogaard model shows a 0.19% to 2.75% reduction in individual 9-year ACE risk-based MHD for left-sided IMNI (P = 0.0015). Risk reduction variations are influenced by dose reduction and other risk factors. Conclusions IMPT provides excellent cardiac protection, particularly for left-sided IMNI and high-risk patients.
No takes yet. Share an insight, caveat, or question.
Cao et al. (2025) conducted an observational in Breast cancer (n=30). Intensity-modulated proton therapy (IMPT) vs. Intensity-modulated radiotherapy (IMRT) was evaluated on Cardiac substructure dose reduction and individual acute coronary events (ACE) risk. Intensity-modulated proton therapy (IMPT) reduced cardiac substructure doses by 63.34% to 100% and lowered estimated individual acute coronary event risk by up to 5.16% compared to IMRT.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: