Bernchou Uffe, Arnold Trine Skak Tranemose, Axelsen Brit, Klüver-Kristensen Mette, Mahmood Faisal, Harbo Frederik Severin Gråe, Asmussen Jon Thor, Hansen Olfred, Bertelsen Anders Smedegaard, Hansen Steinbjørn, Brink Carsten, Dahlrot Rikke Hedegaard
Laboratory of Radiation Physics, Department of Oncology, Odense University Hospital, Denmark; Department of Clinical Research, University of Southern Denmark, Odense, Denmark.
Department of Oncology, Odense University Hospital, Denmark.
Radiother Oncol. 2021 Jul;160:40-46. doi: 10.1016/j.radonc.2021.04.001. Epub 2021 Apr 20.
Tumour growth during radiotherapy may lead to geographical misses of the target volume. This study investigates the evolution of the tumour extent and evaluates the need for plan adaptation to ensure dose coverage of the target in glioblastoma patients.
The prospective study included 29 patients referred for 59.4 Gy in 33 fractions. Magnetic resonance imaging (MRI) was performed at the time of treatment planning, at fraction 10, 20, 30, and three weeks after the end of radiotherapy. The gross tumour volume (GTV) was defined as the T1w contrast-enhanced region plus the surgical cavity on each MRI set. The relative GTV volume and the maximum distance (D) of the extent of the actual GTV outside the original GTV were measured. Based on the location of the actual GTV during radiotherapy and the original planned dose, a prospective clinical decision was made whether to adapt the treatment.
Dose coverage of the GTV during radiotherapy was not compromised, and none of the radiotherapy plans was adapted. The median D (range) was 5.7 (2.0-18.9) mm, 8.0 (2.0-27.4) mm, 8.0 (1.9-27.3) mm, and 8.9 (1.9-34.4) mm at fraction 10, 20, 30, and follow-up. The relative GTV volume and D observed at fraction 10 were correlated with the values observed at follow-up (R = 0.74, p < 0.001 and R = 0.79, p < 0.001, respectively).
Large variations in the GTV extent were observed, and changes often occurred early in the treatment. Plan adaptation for geographical misses was not performed in our cohort due to sufficient CTV margins.
放射治疗期间肿瘤生长可能导致靶区遗漏。本研究调查胶质母细胞瘤患者肿瘤范围的演变，并评估是否需要调整计划以确保靶区剂量覆盖。
前瞻性研究纳入29例接受33次分割、总剂量59.4 Gy治疗的患者。在治疗计划时、第10次、第20次、第30次分割时以及放疗结束后3周进行磁共振成像（MRI）检查。将每个MRI图像上的大体肿瘤体积（GTV）定义为T1加权增强区域加上手术腔。测量相对GTV体积以及实际GTV超出原始GTV范围的最大距离（D）。根据放疗期间实际GTV的位置和原始计划剂量，前瞻性地做出是否调整治疗的临床决策。
放疗期间GTV的剂量覆盖未受影响，且无一例放疗计划进行调整。在第10次、第20次、第30次分割时及随访时，D的中位数（范围）分别为5.7（2.0 - 18.9）mm、8.0（2.0 - 27.4）mm、8.0（1.9 - 27.3）mm和8.9（1.9 - 34.4）mm。在第10次分割时观察到的相对GTV体积和D与随访时观察到的值相关（R分别为0.74，p < 0.001和0.79，p < 0.001）。
观察到GTV范围存在较大差异，且变化常在治疗早期出现。由于CTV有足够的边界，本队列未因靶区遗漏而进行计划调整。
