左侧乳腺癌 VMAT 治疗与 3D-CRT 相比的心肺剂量预测因素：一项回顾性研究。
Predictors of heart and lung dose in left-sided breast cancer treated with VMAT relative to 3D-CRT: A retrospective study.
机构信息
Department of Radiation Oncology, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian Province, China.
出版信息
PLoS One. 2021 Jun 9;16(6):e0252552. doi: 10.1371/journal.pone.0252552. eCollection 2021.
BACKGROUND
Before generating radiotherapy plans for breast cancer patients, the choice of plan techniques (three-dimensional conformal radiation therapy (3D-CRT) and volumetric modulated arc therapy (VMAT)) should be made. This study investigated the performance of two geometric indices in aiding the choice of 3D-CRT and VMAT plans in women undergoing left-sided whole breast radiotherapy.
MATERIALS AND METHODS
119 patients, previously treated with left-sided breast radiotherapy (61 3D-CRT treatments and 58 VMAT treatments) from a single institution, were retrospectively studied. Two geometric indices, which were cardiac junction (CJ) index and pulmonary junction (PJ) index, were defined and the relationship between these indices and dose of organs at risk (OARs) were evaluated. Two-tailed Student's t-test was performed to compare patient characteristics between 3D-CRT and VMAT. Linear regressions were calculated to investigate the association between geometric indices and absorbed dose of heart and left lung, including mean dose of heart (MHD), V5, V30 of heart, and mean dose of left lung (MLLD), V5, V10, V20, V30, V40 of left lung.
RESULTS
The CJ index was strongly correlated with the MHD in 3D-CRT group and VMAT group. The linear regression formulas were MHD = 4826.59 ×CJ Index+310.48 (R = 0.857, F = 163.77, P = 0.000) in 3D-CRT plans and MHD = 1789.29×CJ Index+437.50 (R = 0.45, F = 14.23, P = 0.000) in VMAT plans. The intersection of the two formulas was CJ index = 4.2% and MHD = 512.33 cGy. The PJ index demonstrated a strongly positive correlation with MLLD in 3D-CRT group and VMAT group as well. The linear regression formulas were MLLD = 2879.54×PJ Index+999.79 (R = 0.697, F = 55.86, P = 0.000) in 3D-CRT plans and MLLD = 1411.79×PJ Index+1091.88 (R = 0.676, F = 47.11, P = 0.000) in VMAT plans, the intersection of the two formulas was PJ index = 6.3% and MLLD = 1180.46 cGy.
CONCLUSIONS
CJ index and PJ index could be used as a practical tool to select 3D-CRT or VMAT before generating plans. We recommend that VMAT plan is preferable when CJ index is greater than 4.2% and/or PJ index is greater than 14.6%, while 3D-CRT plan is the first choice in the opposite.
背景
在为乳腺癌患者制定放疗计划之前，应选择计划技术（三维适形放疗（3D-CRT）和容积调强弧形治疗（VMAT））。本研究旨在探讨两种几何指标在辅助选择左侧全乳放疗的女性 3D-CRT 和 VMAT 计划中的性能。
材料与方法
回顾性分析来自单一机构的 119 例左侧乳腺癌放疗患者（61 例 3D-CRT 治疗和 58 例 VMAT 治疗）。定义了两个几何指标，即心脏交界（CJ）指数和肺交界（PJ）指数，并评估了这些指数与危及器官（OAR）剂量的关系。采用两尾学生 t 检验比较 3D-CRT 和 VMAT 两组患者的特征。计算线性回归以研究几何指标与心脏和左肺吸收剂量之间的关系，包括心脏的平均剂量（MHD）、心脏的 V5、V30，以及左肺的平均剂量（MLLD）、左肺的 V5、V10、V20、V30、V40。
结果
在 3D-CRT 组和 VMAT 组中，CJ 指数与 MHD 呈强相关性。3D-CRT 计划中的线性回归公式为 MHD=4826.59×CJ 指数+310.48（R=0.857，F=163.77，P=0.000），VMAT 计划中的线性回归公式为 MHD=1789.29×CJ 指数+437.50（R=0.45，F=14.23，P=0.000）。两个公式的交点为 CJ 指数=4.2%，MHD=512.33 cGy。PJ 指数与 3D-CRT 组和 VMAT 组的 MLLD 也呈强正相关。3D-CRT 计划中的线性回归公式为 MLLD=2879.54×PJ 指数+999.79（R=0.697，F=55.86，P=0.000），VMAT 计划中的线性回归公式为 MLLD=1411.79×PJ 指数+1091.88（R=0.676，F=47.11，P=0.000），两个公式的交点为 PJ 指数=6.3%，MLLD=1180.46 cGy。
结论
CJ 指数和 PJ 指数可作为生成计划前选择 3D-CRT 或 VMAT 的实用工具。我们建议当 CJ 指数大于 4.2%和/或 PJ 指数大于 14.6%时，优先选择 VMAT 计划，而当 CJ 指数小于 4.2%且 PJ 指数小于 14.6%时，优先选择 3D-CRT 计划。
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