Department of Radiation Oncology, MR Linac ART Division, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
Department of Radiation Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo, 113-8677, Japan.
BMC Med Imaging. 2023 Aug 1;23(1):102. doi: 10.1186/s12880-023-01055-w.
Megavoltage computed tomography (MVCT) images acquired during each radiotherapy session may be useful for delta radiomics. However, no studies have examined whether the MVCT-based radiomics has prognostic power. Therefore, the purpose of this study was to examine the prognostic power of the MVCT-based radiomics for head and neck squamous cell carcinoma (HNSCC) patients.
100 HNSCC patients who received definitive radiotherapy were analyzed and divided into two groups: training (n = 70) and test (n = 30) sets. MVCT images obtained using TomoTherapy for the first fraction of radiotherapy and planning kilovoltage CT (kVCT) images obtained using Aquilion LB CT scanner were analyzed. Primary gross tumor volume (GTV) was propagated from kVCT to MVCT images using rigid registration, and 107 radiomic features were extracted from the GTV in MVCT and kVCT images. Least absolute shrinkage and selection operator (LASSO) Cox regression model was used to examine the association between overall survival (OS) and rad score calculated for each patient by weighting the feature value through the coefficient when features were selected. Then, the predictive values of MVCT-based and kVCT-based rad score and patient-, treatment-, and tumor-specific factors were evaluated.
C-indices of the rad score for MVCT- and kVCT-based radiomics were 0.667 and 0.685, respectively. The C-indices of 6 clinical factors were 0.538-0.622. The 3-year OS was significantly different between high- and low-risk groups according to the MVCT-based rad score (50% vs. 83%; p < 0.01).
Our results suggested that MVCT-based radiomics had stronger prognostic power than any single clinical factor and was a useful prognostic factor when predicting OS in HNSCC patients.
在每次放射治疗过程中获取的兆伏级计算机断层扫描（MVCT）图像可能对 delta 放射组学有用。然而，尚无研究探讨基于 MVCT 的放射组学是否具有预后价值。因此，本研究旨在检验基于 MVCT 的放射组学对头颈部鳞状细胞癌（HNSCC）患者的预后价值。
对 100 例接受根治性放疗的 HNSCC 患者进行分析，分为训练集（n=70）和测试集（n=30）。分析了放疗第一阶段使用 TomoTherapy 获得的 MVCT 图像和使用 Aquilion LB CT 扫描仪获得的计划千伏 CT（kVCT）图像。使用刚性配准将原发性大体肿瘤体积（GTV）从 kVCT 传播到 MVCT 图像，从 MVCT 和 kVCT 图像的 GTV 中提取了 107 个放射组学特征。使用最小绝对收缩和选择算子（LASSO）Cox 回归模型，通过对特征值进行加权来检验 OS 与 rad 评分之间的相关性，权重为在选择特征时通过系数计算得到的每个患者的特征值。然后，评估了基于 MVCT 和 kVCT 的 rad 评分以及患者、治疗和肿瘤特异性因素的预测价值。
基于 MVCT 和 kVCT 的放射组学的 rad 评分的 C 指数分别为 0.667 和 0.685。6 个临床因素的 C 指数为 0.538-0.622。根据基于 MVCT 的 rad 评分，高低风险组的 3 年 OS 有显著差异（50% vs. 83%；p<0.01）。
我们的结果表明，基于 MVCT 的放射组学比任何单一临床因素具有更强的预后能力，是预测 HNSCC 患者 OS 的有用预后因素。
