Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA; Division of Therapeutic Radiation and Oncology, King Chulalongkorn Memorial Hospital, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, USA.
Radiother Oncol. 2020 Apr;145:209-214. doi: 10.1016/j.radonc.2020.01.002. Epub 2020 Feb 13.
Patterns of local, regional, and distant failure after stereotactic ablative radiotherapy (SABR) for early-stage non-small cell lung cancer (NSCLC) have been widely reported. However, reliable methods for analyzing causes of local failure are lacking. We describe a method for analyzing and reporting patterns of in-field recurrence after SABR, incorporating dosimetric parameters from initial treatment plan as well as geometric information from diagnostic images at recurrence.
Diagnostic CT images at recurrence were registered with initial treatment planning images and radiation dose by deformable image registration. Recurrent gross tumor volume (rGTV) and centroid (geometric center of rGTV) were delineated. In-field failure was classified as centroids originating within the original planning target volume. Dose-volume histograms for each rGTV were used to further classify in-field recurrences as central high-dose (dose to 95% of rGTV [rGTVD95%] ≥95% of dose prescribed to PTV) or peripheral high-dose (rGTVD95% <95% of dose prescribed to PTV).
634 patients received SABR from 2004 to 2014 with 48 local recurrences. 35 of these had evaluable images with 16 in-field recurrences: 9 central high-dose, 6 peripheral high-dose, and 1 had both. Time to and volume of recurrence were not statistically different between central versus peripheral high-dose recurrences. However mean rGTV dose, mean centroid dose, and rGTVD95% were higher for central versus peripheral high-dose recurrences.
We report a standardized method for analysis and classification of in-field recurrence after SABR. There were more central as opposed to peripheral high-dose recurrences, suggesting biological rather than technical issues underlying majority of in-field failures.
立体定向消融放疗（SABR）治疗早期非小细胞肺癌（NSCLC）后的局部、区域和远处失败模式已被广泛报道。然而，缺乏分析局部失败原因的可靠方法。我们描述了一种分析和报告 SABR 后野内复发模式的方法，该方法结合了初始治疗计划中的剂量学参数以及复发时诊断图像的几何信息。
将复发时的诊断 CT 图像与初始治疗计划图像和辐射剂量通过变形图像配准进行配准。勾画复发的大体肿瘤体积（rGTV）和中心点（rGTV 的几何中心）。野内失败被归类为中心点起源于原始计划靶区内部。每个 rGTV 的剂量-体积直方图用于进一步将野内复发分为中央高剂量（rGTVD95% 剂量至 95%的 rGTV [rGTVD95%] ≥PTV 规定剂量的 95%）或外周高剂量（rGTVD95% <PTV 规定剂量的 95%）。
2004 年至 2014 年，634 例患者接受了 SABR 治疗，其中 48 例出现局部复发。其中 35 例有可评估的图像，其中 16 例出现野内复发：9 例中央高剂量，6 例外周高剂量，1 例两者兼有。中央高剂量与外周高剂量复发之间的时间和复发体积无统计学差异。然而，中央高剂量与外周高剂量复发相比，rGTV 平均剂量、中心点平均剂量和 rGTVD95%更高。
我们报告了一种用于分析和分类 SABR 后野内复发的标准化方法。中央高剂量复发的比例高于外周高剂量复发，这表明大多数野内失败的原因是生物学因素而非技术因素。
