Abstract：
OBJECTIVE: Stereotactic ablative body radiotherapy (SABR) is increasingly used for early-stage lung cancer, however the impact of dose to the heart and cardiac substructures remains largely unknown. The study investigated doses received by cardiac substructures in SABR patients and impact on survival.
METHODS: SSBROC is an Australian multi-centre phase II prospective study of SABR for stage I non-small cell lung cancer. Patients were treated between 2013 and 2019 across 9 centres. In this secondary analysis of the dataset, a previously published and locally developed open-source hybrid deep learning cardiac substructure automatic segmentation tool was deployed on the planning CTs of 117 trial patients. Physical doses to 18 cardiac structures and EQD2 converted doses (α/β = 3) were calculated. Endpoints evaluated include pericardial effusion and overall survival. Associations between cardiac doses and survival were analysed with the Kaplan-Meier method and Cox proportional hazards models.
RESULTS: Cardiac structures that received the highest physical mean doses were superior vena cava (22.5 Gy) and sinoatrial node (18.3 Gy). The highest physical maximum dose was received by the heart (51.7 Gy) and right atrium (45.3 Gy). Three patients developed grade 2, and one grade 3 pericardial effusion. The cohort receiving higher than median mean heart dose (MHD) had poorer survival compared to those who received below median MHD (p = 0.00004). On multivariable Cox analysis, male gender and maximum dose to ascending aorta were significant for worse survival.
CONCLUSIONS: Patients treated with lung SABR may receive high doses to cardiac substructures. Dichotomising the patients according to median mean heart dose showed a clear difference in survival. On multivariable analyses gender and dose to ascending aorta were significant for survival, however cardiac substructure dosimetry and outcomes should be further explored in larger studies.
METHODS: SSBROC is an Australian multi-centre phase II prospective study of SABR for stage I non-small cell lung cancer. Patients were treated between 2013 and 2019 across 9 centres. In this secondary analysis of the dataset, a previously published and locally developed open-source hybrid deep learning cardiac substructure automatic segmentation tool was deployed on the planning CTs of 117 trial patients. Physical doses to 18 cardiac structures and EQD2 converted doses (α/β = 3) were calculated. Endpoints evaluated include pericardial effusion and overall survival. Associations between cardiac doses and survival were analysed with the Kaplan-Meier method and Cox proportional hazards models.
RESULTS: Cardiac structures that received the highest physical mean doses were superior vena cava (22.5 Gy) and sinoatrial node (18.3 Gy). The highest physical maximum dose was received by the heart (51.7 Gy) and right atrium (45.3 Gy). Three patients developed grade 2, and one grade 3 pericardial effusion. The cohort receiving higher than median mean heart dose (MHD) had poorer survival compared to those who received below median MHD (p = 0.00004). On multivariable Cox analysis, male gender and maximum dose to ascending aorta were significant for worse survival.
CONCLUSIONS: Patients treated with lung SABR may receive high doses to cardiac substructures. Dichotomising the patients according to median mean heart dose showed a clear difference in survival. On multivariable analyses gender and dose to ascending aorta were significant for survival, however cardiac substructure dosimetry and outcomes should be further explored in larger studies.
摘要：
目的：立体定向消融体放疗（SABR）越来越多地用于早期肺癌，然而,剂量对心脏和心脏亚结构的影响在很大程度上仍然未知.该研究调查了SABR患者心脏亚结构接受的剂量及其对生存的影响。
方法：SSBROC是一项澳大利亚多中心II期SABR治疗I期非小细胞肺癌的前瞻性研究。患者在2013年至2019年期间在9个中心接受治疗。在对数据集的二次分析中，我们在117例试验患者的计划CT上部署了之前发布的本地开发的开源混合深度学习心脏子结构自动分割工具.计算18个心脏结构的物理剂量和EQD2转换剂量(α/β=3)。评估的终点包括心包积液和总生存率。使用Kaplan-Meier方法和Cox比例风险模型分析了心脏剂量与生存率之间的关联。
结果：接受最高物理平均剂量的心脏结构是上腔静脉（22.5Gy）和窦房结（18.3Gy）。心脏（51.7Gy）和右心房（45.3Gy）接受了最高的物理最大剂量。3例患者发展为2级，1例发展为3级心包积液。与接受低于中位数MHD的人群相比，接受高于中位数平均心脏剂量（MHD）的人群的生存率较差（p=0.00004）。关于多变量Cox分析，男性和升主动脉的最大剂量对较差的生存率有显著影响.
结论：接受肺SABR治疗的患者可以接受高剂量的心脏亚结构治疗。根据中位平均心脏剂量对患者进行二分显示出明显的生存率差异。在多变量分析中，性别和升主动脉剂量对生存有重要意义，然而,心脏亚结构剂量学和结局应在更大的研究中进一步探讨.
方法：SSBROC是一项澳大利亚多中心II期SABR治疗I期非小细胞肺癌的前瞻性研究。患者在2013年至2019年期间在9个中心接受治疗。在对数据集的二次分析中，我们在117例试验患者的计划CT上部署了之前发布的本地开发的开源混合深度学习心脏子结构自动分割工具.计算18个心脏结构的物理剂量和EQD2转换剂量(α/β=3)。评估的终点包括心包积液和总生存率。使用Kaplan-Meier方法和Cox比例风险模型分析了心脏剂量与生存率之间的关联。
结果：接受最高物理平均剂量的心脏结构是上腔静脉（22.5Gy）和窦房结（18.3Gy）。心脏（51.7Gy）和右心房（45.3Gy）接受了最高的物理最大剂量。3例患者发展为2级，1例发展为3级心包积液。与接受低于中位数MHD的人群相比，接受高于中位数平均心脏剂量（MHD）的人群的生存率较差（p=0.00004）。关于多变量Cox分析，男性和升主动脉的最大剂量对较差的生存率有显著影响.
结论：接受肺SABR治疗的患者可以接受高剂量的心脏亚结构治疗。根据中位平均心脏剂量对患者进行二分显示出明显的生存率差异。在多变量分析中，性别和升主动脉剂量对生存有重要意义，然而,心脏亚结构剂量学和结局应在更大的研究中进一步探讨.
