Department of Radiation Oncology, Klinikum rechts der Isar, TU München, Ismaninger Str. 22, 81675, Munich, Germany.
Partner Site Munich, Deutsches Konsortium für Translationale Krebsforschung (DKTK), Munich, Germany.
Strahlenther Onkol. 2020 Apr;196(4):368-375. doi: 10.1007/s00066-020-01587-y. Epub 2020 Feb 3.
There are different contouring guidelines for definition of the clinical target volume (CTV) for intensity-modulated radiation therapy (IMRT) of anal cancer (AC). We conducted a planning comparison study to evaluate and compare the dose to relevant organs at risk (OARs) while using different CTV definitions.
Twelve patients with a primary diagnosis of anal cancer, who were treated with primary chemoradiation (CRT), were selected. We generated four guideline-specific CTVs and subsequently planned target volumes (PTVs) on the planning CT scan of each patient. An IMRT plan for volumetric arc therapy (VMAT) was set up for each PTV. Dose parameters of the planned target volume (PTV) and OARs were evaluated and compared, too.
The mean volume of the four PTVs ranged from 2138 cc to 2433 cc. The target volumes contoured by the authors based on the recommendations of each group were similar in the pelvis, while they differed significantly in the inguinal region. There were no significant differences between the four target volumes with regard to the dose parameters of the cranially located OARs. Conversely, some dose parameters concerning the genitals and the skin varied significantly among the different guidelines.
The four contouring guidelines differ significantly concerning the inguinal region. In order to avoid inguinal recurrence and to protect relevant OARs, further investigations are needed to generate uniform standards for definition of the elective clinical target volume in the inguinal region.
针对肛门癌（AC）调强放疗（IMRT）的临床靶区（CTV）定义，存在不同的勾画指南。我们进行了一项计划比较研究，以评估和比较使用不同CTV 定义时相关危及器官（OAR）的剂量。
选择了 12 名经病理证实为原发性肛门癌、接受同步放化疗（CRT）的患者。我们为每位患者的计划 CT 扫描生成了四个指南特异性 CTV，并随后规划了靶区（PTV）。为每个 PTV 设立了容积旋转调强放疗（VMAT）的 IMRT 计划。评估和比较了计划靶区（PTV）和 OAR 的剂量参数。
四个 PTV 的平均体积范围为 2138cc 至 2433cc。根据每组建议勾画的作者的靶区在骨盆内相似，但在腹股沟区域差异显著。对于颅顶 OAR 的剂量参数，四个靶区之间没有显著差异。相反，不同指南之间关于生殖器和皮肤的一些剂量参数存在显著差异。
四个勾画指南在腹股沟区域有显著差异。为了避免腹股沟复发和保护相关 OAR，需要进一步研究，为腹股沟区域的选择性临床靶区定义生成统一标准。
