Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado.
Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado.
Int J Radiat Oncol Biol Phys. 2020 Apr 1;106(5):1063-1070. doi: 10.1016/j.ijrobp.2019.12.013. Epub 2020 Jan 23.
Studies have noted a link between radiation dose to the heart and overall survival (OS) for patients with lung cancer treated with chemoradiation. The purpose of this study was to characterize pre- to posttreatment cardiac metabolic changes using fluorodeoxyglucose/positron emission tomography (FDG-PET) images and to evaluate whether changes in cardiac metabolism predict for OS.
Thirty-nine patients enrolled in a functional avoidance prospective study who had undergone pre- and postchemoradiation FDG-PET imaging were evaluated. For each patient, the pretreatment and posttreatment PET/CTs were rigidly registered to the planning CT, dose, and structure set. PET-based metabolic dose-response was assessed by comparing pretreatment to posttreatment mean standardized uptake values (SUVmean) in the heart as a function of dose-bin. OS analysis was performed by comparing SUVmean changes for patients who were alive or had died at last follow-up and by using a multivariate model to assess whether pre- to posttreatment SUVmean changes were a predictor of OS.
The dose-response curve revealed increasing changes in SUV as a function of cardiac dose with an average SUVmean increase of 1.7% per 10 Gy. Patients were followed for a median of 437 days (range, 201-1131 days). SUVmean change was significantly predictive of OS on multivariate analysis with a hazard ratio of 0.541 (95% confidence intervals, 0.312-0.937). Patients alive at follow-up had an average increase of 17.2% in cardiac SUVmean while patients that died had an average decrease in SUVmean decrease of 13.5% (P = .048).
Our data demonstrated that posttreatment SUV changes in the heart were significant indicators of dose-response and predictors of OS. The present work is hypothesis generating and must be validated in an independent cohort. If validated, our data show the potential for cardiac metabolic changes to be an early predictor for clinical outcomes.
已有研究指出，肺癌患者接受放化疗后，心脏所受辐射剂量与总体生存率（OS）之间存在关联。本研究旨在通过氟脱氧葡萄糖/正电子发射断层扫描（FDG-PET）图像来描述治疗前后心脏代谢的变化，并评估心脏代谢变化是否可以预测 OS。
本研究共纳入 39 例接受放化疗前、后 FDG-PET 成像的功能性回避前瞻性研究患者。对于每位患者，将治疗前和治疗后的 PET/CT 与计划 CT、剂量和结构集进行刚性配准。通过比较心脏的治疗前后平均标准化摄取值（SUVmean）与剂量箱的关系，评估基于 PET 的代谢剂量反应。通过比较存活和死亡患者的 SUVmean 变化进行 OS 分析，并使用多变量模型评估治疗前后 SUVmean 变化是否是 OS 的预测因素。
剂量反应曲线显示，随着心脏剂量的增加，SUV 呈递增变化，平均 SUVmean 每增加 10 Gy 增加 1.7%。患者的中位随访时间为 437 天（范围为 201-1131 天）。多变量分析显示，SUVmean 变化与 OS 显著相关，风险比为 0.541（95%置信区间为 0.312-0.937）。随访时存活的患者心脏 SUVmean 平均增加 17.2%，而死亡的患者 SUVmean 平均降低 13.5%（P=0.048）。
我们的数据表明，心脏的治疗后 SUV 变化是剂量反应和 OS 预测的重要指标。目前的工作只是提出假设，需要在独立队列中进行验证。如果得到验证，我们的数据表明心脏代谢变化有可能成为临床结果的早期预测指标。
