Reshko Leonid B, Kalman Noah S, Hugo Geoffrey D, Weiss Elisabeth
Department of Education, Riverside Regional Medical Center, Newport News, VA, USA.
Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, USA.
J Thorac Dis. 2018 Apr;10(4):2346-2356. doi: 10.21037/jtd.2018.04.42.
The impact of radiation dose to the heart in early-stage lung cancer patients treated with definitive stereotactic body radiation therapy (SBRT) is not well known. We, therefore, analyzed whether higher radiation dose to the heart would lead to an increase in cardiac toxicity and overall mortality.
Seventy-four patients with 75 tumors treated definitively with SBRT for early-stage non-small cell lung cancer (NSCLC) and two cases of limited-stage small cell lung cancer (SCLC) with an average follow-up of 35 months (range, 1-130 months) were retrospectively analyzed. The whole heart and cardiac substructures including atria, ventricles, heart valves, atrioventricular (AV) node and four major coronary artery branches were contoured using commercial treatment planning software. For each structure, multiple dose-volume parameters were recorded. The relation between radiation doses to the heart, tumor location, and preexisting medical conditions with the development of cardiac events and mortality was assessed.
Overall, there was large variability in dose to cardiac substructures: mean heart dose (MHD) averaged 1.90 Gy (range, 0.04-11.00 Gy) equivalent 2 Gy dose (EQD2) and average max dose to the left anterior descending artery (LAD) was 5.67 Gy (range, 0.04-48.60 Gy) EQD2. Patients with tumor location in the upper lobes received higher cardiac radiation dose compared to other lobes (P<0.0001). There was no difference in MHD between central and peripheral tumor locations. The distance between heart and tumor was negatively associated with MHD (r=-0.61, P<0.0001). Eighteen patients developed cardiac complications including the need for defibrillator placement, arrhythmia development and worsening heart failure. Preexisting cardiac disease was associated with an increased number of cardiac events after radiotherapy (P=0.039). However, neither radiation dose to the whole heart or the cardiac substructures, nor comorbidities such as diabetes, hypercholesterolemia, hypertension or COPD were associated with the number of cardiac events or overall mortality.
Radiation doses to the heart and its substructures show large variability. Cardiac events occurred more frequently in patients with a history of heart problems. At present, the effect of radiation dose on cardiac toxicity is unclear in patients undergoing SBRT for early-stage lung cancer. Longer follow-up and a larger cohort are needed to assess for late cardiac sequelae.
在接受立体定向体部放射治疗（SBRT）的早期肺癌患者中，心脏所受辐射剂量的影响尚不清楚。因此，我们分析了较高的心脏辐射剂量是否会导致心脏毒性增加和总死亡率上升。
回顾性分析了74例接受SBRT根治性治疗的75例早期非小细胞肺癌（NSCLC）患者以及2例局限期小细胞肺癌（SCLC）患者，平均随访35个月（范围1 - 130个月）。使用商业治疗计划软件勾勒出整个心脏和心脏亚结构，包括心房、心室、心脏瓣膜、房室（AV）结和四条主要冠状动脉分支。对于每个结构，记录多个剂量 - 体积参数。评估心脏辐射剂量、肿瘤位置和既往病史与心脏事件发生及死亡率之间的关系。
总体而言，心脏亚结构的剂量差异很大：平均心脏剂量（MHD）平均为1.90 Gy（范围0.04 - 11.00 Gy）等效2 Gy剂量（EQD2），左前降支动脉（LAD）的平均最大剂量为5.67 Gy（范围0.04 - 48.60 Gy）EQD2。肿瘤位于上叶的患者比其他叶接受的心脏辐射剂量更高（P<0.0001）。中央和外周肿瘤位置的MHD无差异。心脏与肿瘤之间的距离与MHD呈负相关（r = -0.61，P<0.0001）。18例患者出现心脏并发症，包括需要植入除颤器、发生心律失常和心力衰竭加重。既往有心脏病与放疗后心脏事件数量增加相关（P = 0.039）。然而，无论是对整个心脏或心脏亚结构的辐射剂量，还是糖尿病、高胆固醇血症、高血压或慢性阻塞性肺疾病（COPD）等合并症，均与心脏事件数量或总死亡率无关。
心脏及其亚结构的辐射剂量差异很大。有心脏问题病史的患者心脏事件发生频率更高。目前，对于接受SBRT治疗的早期肺癌患者，辐射剂量对心脏毒性的影响尚不清楚。需要更长时间的随访和更大的队列来评估晚期心脏后遗症。
