Cao Lu, Zhao Han, Zhang Shujun, Liao Keman, Chen Mei, Cai Gang, Ou Dan, Yang Jing, Wu Xiaoyu, Li Huan, Xu Feifei, Qi Weixiang, Zhang Yibin, Chen Jiayi
Department of Radiation Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Shanghai Key Laboratory of Proton Therapy, Shanghai, China.
Int J Part Ther. 2025 May 26;17:100752. doi: 10.1016/j.ijpt.2025.100752. eCollection 2025 Sep.
Intensity-modulated proton therapy (IMPT) significantly reduces mean heart dose (MHD), but data on cardiac substructure dose and toxicity compared to intensity-modulated radiation therapy (IMRT) are limited. This study evaluated dose reduction in cardiac substructures between IMPT and IMRT and assessed cardiac toxicity risks using 2 normal tissue complication probability models.
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. Normal tissue complication probability models were used to compare individual acute coronary events (ACEs) risk between IMPT and IMRT.
Intensity-modulated proton therapy 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 left anterior descending coronary artery ( = .009), 79.45% for RV ( < .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 ( = .001) and 0.59% to 1.05% for right-sided IMNI ( = .063). The Bogaard model shows a 0.19% to 2.75% reduction in individual 9-year ACE risk-based MHD for left-sided IMNI ( = .0015). Risk reduction variations are influenced by dose reduction and other risk factors.
Intensity-modulated proton therapy provides excellent cardiac protection, particularly for left-sided IMNI and high-risk patients.
调强质子治疗（IMPT）可显著降低平均心脏剂量（MHD），但与调强放射治疗（IMRT）相比，关于心脏亚结构剂量和毒性的数据有限。本研究评估了IMPT和IMRT之间心脏亚结构的剂量降低情况，并使用两种正常组织并发症概率模型评估心脏毒性风险。
对一项随机试验中30例接受IMRT且MHD最高的乳腺癌患者进行回顾性分析。为15次分割的4005 cGy（RBE）处方剂量创建IMPT计划。使用正常组织并发症概率模型比较IMPT和IMRT之间个体急性冠状动脉事件（ACEs）风险。
调强质子治疗使心脏亚结构剂量降低了63.34%至100%，左侧患者的绝对降低幅度更大，右侧患者的相对降低幅度更大。对于左侧内乳淋巴结照射（IMNI），IMPT使左前降支冠状动脉的剂量降低了82.25%（P = 0.009），右心室降低了79.45%（P < 0.001），其他亚结构降低了90%以上。右侧患者大多数亚结构的平均剂量接近零。Darby模型表明，IMPT使左侧IMNI的个体ACE风险降低了1.58%至5.16%（P = 0.001），右侧IMNI降低了0.59%至1.05%（P = 0.063）。Bogaard模型显示，基于个体9年ACE风险的MHD，左侧IMNI降低了0.19%至2.75%（P = 0.0015）。风险降低的差异受剂量降低和其他风险因素的影响。
调强质子治疗提供了出色的心脏保护，特别是对于左侧IMNI和高危患者。
