Department of Cardiology Westmead Hospital Sydney NSW Australia.
Westmead Clinical School University of Sydney NSW Australia.
J Am Heart Assoc. 2021 Apr 6;10(7):e019476. doi: 10.1161/JAHA.120.019476. Epub 2021 Mar 20.
Background Subclinical left ventricular dysfunction detected by 2-dimensional global longitudinal strain post breast radiotherapy has been described in patients with breast cancer. We hypothesized that left ventricular dysfunction postradiotherapy may be site specific, based on differential segmental radiotherapy dose received. Methods and Results Transthoracic echocardiograms were performed at baseline, 6 weeks, and 12 months postradiotherapy on 61 chemotherapy-naïve women with left-sided breast cancer undergoing tangential breast radiotherapy. Radiation received within basal, mid, and apical regions for the 6 left ventricular walls was quantified from the radiotherapy treatment planning system. Anterior, anteroseptal, and anterolateral walls received the highest radiation doses, while inferolateral and inferior walls received the lowest. There was a progressive increase in the radiation dose received from basal to apical regions. At 6 weeks, the most significant percentage deterioration in strain was seen in the apical region, with greatest reductions in the anterior wall followed by the anteroseptal and anterolateral walls, with a similar pattern persisting at 12 months. There was a within-patient dose-response association between the segment-specific percentage deterioration in strain at 6 weeks and 12 months and the radiation dose received. Conclusions Radiotherapy for left-sided breast cancer causes differential segmental dysfunction, with myocardial segments that receive the highest radiation dose demonstrating greatest strain impairment. Percentage deterioration in strain observed 6 weeks postradiotherapy persisted at 12 months and demonstrated a dose-response relationship with radiotherapy dose received. Radiotherapy-induced subclinical cardiac dysfunction is of importance because it could be additive to chemotherapy-related cardiotoxicity in patients with breast cancer. Long-term outcomes in patients with asymptomatic strain reduction require further investigation.
在接受乳腺癌放射治疗后，患者的左心室功能障碍可通过二维整体纵向应变检测到亚临床表现。我们假设，根据接受的不同节段放射剂量，放射治疗后的左心室功能障碍可能具有特定部位的特征。
对 61 例接受切线式乳房放射治疗的左侧乳腺癌且未接受过化疗的女性患者，在放射治疗后 6 周和 12 个月时进行了经胸超声心动图检查。从放射治疗计划系统中量化了左心室 6 个壁的基底、中部和心尖区域接受的辐射剂量。前壁、前间隔壁和前侧壁接受的辐射剂量最高，而下外侧壁和下壁接受的辐射剂量最低。从基底到心尖区域，接受的辐射剂量逐渐增加。在 6 周时，应变的百分比恶化最显著的区域是心尖区域，前壁的降幅最大，其次是前间隔壁和前侧壁，这种模式在 12 个月时仍然存在。在 6 周和 12 个月时，应变的节段特异性百分比恶化与接受的辐射剂量之间存在患者内的剂量反应关系。
左侧乳腺癌的放射治疗会导致节段性的功能障碍，接受最高辐射剂量的心肌节段显示出最大的应变损伤。放射治疗后 6 周观察到的应变百分比恶化在 12 个月时仍然存在，并与接受的放射治疗剂量呈剂量反应关系。放射治疗引起的亚临床心脏功能障碍很重要，因为它可能会加重乳腺癌患者化疗相关的心脏毒性。需要进一步研究无症状应变减少的患者的长期结局。
