Department of Oncology, Copenhagen University Hospital - Herlev and Gentofte, Copenhagen, Denmark; Department of Health Technology, Technical University of Denmark, Roskilde, Denmark.
Department of Oncology, Copenhagen University Hospital - Herlev and Gentofte, Copenhagen, Denmark; Department of Health Technology, Technical University of Denmark, Roskilde, Denmark.
Radiother Oncol. 2022 Nov;176:92-98. doi: 10.1016/j.radonc.2022.09.015. Epub 2022 Sep 27.
Online adaptive radiotherapy (oART) potentially spares OARs as PTV margins are reduced. This study evaluates dosimetric benefits, compared to standard non-adaptive radiotherapy (non-ART), target propagation methods, and first clinical treatments of CBCT-guided oART of anal cancer.
Treatment plans with standard non-ART and reduced oART PTV margins were retrospectively generated for 23 consecutive patients with anal cancer. For five patients randomly selected among the 23 patients, weekly CBCT-guided oART sessions were simulated, where the targets were either deformed or rigidly propagated. Preferred target propagation method and dose to OARs were evaluated. Ten consecutive patients with anal cancer were treated with CBCT-guided oART. Target propagation methods and oART procedure time were evaluated.
For the retrospective treatment plans, oART resulted in median reductions in bowel bag V of 11.4 % and bladder V of 16.1%. Corresponding values for the simulated sessions were 7.5% and 27.1%. In the simulated sessions, 35% of all targets were deformed while 65% were rigidly propagated. Manual editing and rigid propagation were necessary to obtain acceptable target coverage. In the clinical treatments, the primary and some elective targets were rigidly propagated, while other targets were deformed. The median oART procedure time, measured from CBCT acquisition to completion of plan review and QA, was 23 min.
Simulated oART reduced the dose to OARs, indicating potential reduction in toxicity. Rigid propagation of targets was necessary to reduce the need for manual edit. Clinical treatments demonstrated that oART of anal cancer is feasible but time-consuming.
在线自适应放疗（oART）通过减少 PTV 边界来保护 OAR。本研究评估了与标准非自适应放疗（non-ART）相比，靶区运动管理方法以及首次应用锥形束 CT（CBCT）引导的肛门癌 oART 的临床治疗的剂量学优势。
回顾性地为 23 例肛门癌患者生成了标准 non-ART 和减少 oART PTV 边界的治疗计划。在 23 例患者中随机选择了 5 例患者，模拟每周一次的 CBCT 引导的 oART 治疗，其中靶区可以变形或刚性传播。评估了首选的靶区运动管理方法和 OAR 剂量。10 例肛门癌患者接受了 CBCT 引导的 oART 治疗。评估了靶区运动管理方法和 oART 治疗时间。
对于回顾性治疗计划，oART 导致中位肠袋 V 减少 11.4%，膀胱 V 减少 16.1%。模拟治疗的相应值为 7.5%和 27.1%。在模拟治疗中，所有靶区的 35%发生变形，65%发生刚性传播。为了获得可接受的靶区覆盖，需要手动编辑和刚性传播。在临床治疗中，主要和一些选择性靶区发生刚性传播，而其他靶区发生变形。从 CBCT 采集到计划审查和 QA 完成，oART 治疗的中位数时间为 23 分钟。
模拟 oART 降低了 OAR 剂量，表明可能降低了毒性。为了减少手动编辑的需求，需要对靶区进行刚性传播。临床治疗表明，肛门癌的 oART 是可行的，但耗时。
