Yu Anthony F, White Charlie, Zhang Zhigang, Liu Jennifer E, Gillespie Erin F, McCormick Beryl, Khan Atif J, Steingart Richard M, Powell Simon N, Cahlon Oren, Braunstein Lior Z
Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York.
Department of Biostatistics Memorial Sloan Kettering Cancer Center, New York, New York.
Adv Radiat Oncol. 2024 Jul 25;9(10):101581. doi: 10.1016/j.adro.2024.101581. eCollection 2024 Oct.
Regional nodal irradiation (RNI) for breast cancer yields improvements in disease outcomes, yet comprehensive target coverage often increases cardiac radiation therapy (RT) dose. Volumetric modulated arc therapy (VMAT) may mitigate high-dose cardiac exposure, although it often increases the volume of low-dose exposure. The cardiac implications of this dosimetric configuration (in contrast to historic 3D conformal techniques) remain uncertain.
Eligible patients receiving adjuvant RNI using VMAT for locoregional breast cancer were prospectively enrolled in an IRB-approved study. Echocardiograms were performed prior to RT, at the conclusion of RT, and 6 months following RT. Echocardiographic parameters were measured by a single reader and measures were compared pre- and post-RT via the signed-rank test. Changes in echocardiographic parameters over time were compared to mean and max heart doses via the Spearman correlation test.
Among 19 evaluable patients (median age 38 years), 89% (n = 17) received doxorubicin and 37% (n = 7) received trastuzumab/pertuzumab combination therapy. All patients received VMAT-based whole-breast/chest wall and RNI. The average mean heart dose was 456 cGy (range, 187-697 cGy) and the average max heart dose was 3001 cGy (1560-4793 cGy). Among salient echocardiographic parameters, no significant decrement in cardiac function was observed when comparing pre-RT to 6 months post-RT: mean left ventricular ejection fraction (LVEF) was 61.8% (SD 4.4%) pre-RT and 62.7% (SD 3.8%) 6 months post-RT ( = .493); mean global longitudinal strain (GLS) was -19.3% (SD 2.2%) pre-RT and -19.6% (SD 1.8%) 6 months post-RT ( = .627). No individual patient exhibited reduced LVEF or sustained decrement in GLS. No correlations were observed for changes in LVEF or GLS when compared to mean or maximum heart doses ( > .1 for all).
VMAT for left-sided RNI yielded no significant early decrement in echocardiographic parameters of cardiac function, including LVEF and GLS, within this limited cohort. No patient exhibited significant LVEF changes, and none exhibited sustained decrements in GLS. VMAT may be a reasonable approach to cardiac avoidance in patients requiring RNI, including those receiving anthracyclines and HER2-directed therapy. Larger cohorts with longer follow-ups will be needed to validate these findings.
乳腺癌区域淋巴结照射（RNI）可改善疾病预后，但全面的靶区覆盖通常会增加心脏放疗（RT）剂量。容积调强弧形放疗（VMAT）可能会减轻高剂量心脏照射，尽管它通常会增加低剂量照射的体积。这种剂量学配置（与传统的三维适形技术相比）对心脏的影响仍不确定。
符合条件的局部区域乳腺癌患者采用VMAT进行辅助RNI，并前瞻性纳入一项经机构审查委员会批准的研究。在放疗前、放疗结束时和放疗后6个月进行超声心动图检查。超声心动图参数由一名阅片者测量，并通过符号秩检验比较放疗前后的测量值。通过Spearman相关检验将超声心动图参数随时间的变化与平均心脏剂量和最大心脏剂量进行比较。
在19例可评估患者（中位年龄38岁）中，89%（n = 17）接受了阿霉素治疗，37%（n = 7）接受了曲妥珠单抗/帕妥珠单抗联合治疗。所有患者均接受基于VMAT的全乳/胸壁和RNI。平均心脏平均剂量为456 cGy（范围187 - 697 cGy），平均心脏最大剂量为3001 cGy（1560 - 4793 cGy）。在显著的超声心动图参数中，比较放疗前与放疗后6个月时，未观察到心脏功能有显著下降：放疗前平均左心室射血分数（LVEF）为61.8%（标准差4.4%），放疗后6个月为62.7%（标准差3.8%）（P = 0.493）；放疗前平均整体纵向应变（GLS）为 - 19.3%（标准差2.2%），放疗后6个月为 - 19.6%（标准差1.8%）（P = 0.627）。没有个体患者出现LVEF降低或GLS持续下降。与平均或最大心脏剂量相比，未观察到LVEF或GLS变化之间的相关性（所有P>0.1）。
在这个有限的队列中，左侧RNI采用VMAT在超声心动图心脏功能参数（包括LVEF和GLS）方面未产生显著的早期下降。没有患者出现显著的LVEF变化，也没有患者出现GLS的持续下降。对于需要RNI的患者，包括接受蒽环类药物和HER2靶向治疗的患者，VMAT可能是一种合理的心脏保护方法。需要更大的队列和更长时间的随访来验证这些发现。
