Hansen Christian Rønn, Bertelsen Anders S, Hazell Irene, Stougaard Sarah W, Johansen Jørgen, Overgaard Jens, Eriksen Jesper Grau, Zukauskaite Ruta
Laboratory of Radiation Physics, Odense University Hospital, Odense, Denmark; Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Research, University of Southern Denmark, Odense, Denmark.
Laboratory of Radiation Physics, Odense University Hospital, Odense, Denmark.
Acta Oncol. 2025 Sep 11;64:1205-1211. doi: 10.2340/1651-226X.2025.44049.
Radiotherapy for head and neck cancer must balance tumour control with late toxicities such as dysphagia and xerostomia. Recent retrospective studies suggest that the margin from the gross tumour volume (GTV) to the high-dose clinical target volume (CTV1) may not be critical for local control, while larger irradiated volumes increase the risk of toxicity. The study quantifies potential reductions in dose to organs at risk (OARs) and predicted dysphagia risk when the standard 5 mm GTV-to-CTV1 margin is eliminated in oropharyngeal cancer. Patient/material and methods: Retrospectively 30 oropharyngeal cancer patients treated consecutively during 2023 according to the DAHANCA guidelines (5 mm GTV-to-CTV1 margin) were selected. For each patient, a standard plan and a modified experimental plan (CTV1 = GTV, and CTV2 reduced by 5 mm accordingly) were generated using Pinnacle3 Auto-Planning. All plans met the DAHANCA target coverage and OAR dose constraints. Dose-volume data for relevant OARs were extracted and compared in MATLAB. Normal tissue complication probability (NTCP) model for dysphagia was applied.
Margin elimination reduced high-dose CTV volumes by 70%, yielding significant dose reductions to multiple OARs. Mean doses to the upper/middle pharyngeal constrictors decreased by around 4-5 Gy (p < 0.001) and to the contralateral submandibular gland by ~5 Gy (p < 0.001). These dosimetric gains correspond to an estimated median ΔNTCP of 6.0% of late grade ≥ 2 dysphagia. Target coverage and conformity were maintained in all plans.
Omitting the high-risk CTV margin can substantially reduce the dose to dysphagia--associated OAR without compromising target coverage. This approach shows promise for improving patient-reported swallowing outcomes and warrants clinical evaluation.
头颈癌放疗必须在肿瘤控制与吞咽困难和口干等晚期毒性之间取得平衡。最近的回顾性研究表明，从大体肿瘤体积（GTV）到高剂量临床靶体积（CTV1）的边界对于局部控制可能并非关键因素，而较大的照射体积会增加毒性风险。本研究量化了口咽癌中消除标准的5毫米GTV到CTV1边界时，危及器官（OARs）剂量的潜在降低以及预测的吞咽困难风险。患者/材料与方法：回顾性选取2023年期间按照DAHANCA指南（5毫米GTV到CTV1边界）连续治疗的30例口咽癌患者。对于每位患者，使用Pinnacle3自动计划生成一个标准计划和一个修改后的实验计划（CTV1 = GTV，CTV2相应减少5毫米）。所有计划均满足DAHANCA靶区覆盖和OAR剂量限制。在MATLAB中提取并比较相关OARs的剂量体积数据。应用吞咽困难的正常组织并发症概率（NTCP）模型。
消除边界使高剂量CTV体积减少70%，多个OARs的剂量显著降低。咽上/中缩肌的平均剂量降低约4 - 5 Gy（p < 0.001），对侧下颌下腺的平均剂量降低约5 Gy（p < 0.001）。这些剂量学上的获益对应于晚期≥2级吞咽困难估计中位ΔNTCP为6.0%。所有计划均维持了靶区覆盖和适形性。
省略高危CTV边界可在不影响靶区覆盖的情况下大幅降低与吞咽困难相关的OARs剂量。这种方法有望改善患者报告的吞咽结果，值得进行临床评估。
