Department of Clinical Oncology, The University of Hong Kong, Queen Mary Hospital, Hong Kong.
Int J Radiat Oncol Biol Phys. 2012 Sep 1;84(1):176-82. doi: 10.1016/j.ijrobp.2011.10.010. Epub 2012 Jan 13.
We wanted to investigate dosimetric parameters that would predict radiation-induced acute nausea and vomiting in intensity-modulated radiation therapy (IMRT) for undifferentiated carcinoma of the nasopharynx (NPC).
Forty-nine consecutive patients with newly diagnosed NPC were treated with IMRT alone in this prospective study. Patients receiving any form of chemotherapy were excluded. The dorsal vagal complex (DVC) as well as the left and right vestibules (VB-L and VB-R, respectively) were contoured on planning computed tomography images. A structure combining both the VB-L and the VB-R, named VB-T, was also generated. All structures were labeled organs at risk (OAR). A 3-mm three-dimensional margin was added to these structures and labeled DVC+3 mm, VB-L+3 mm, VB-R+3 mm, and VB-T+3 mm to account for physiological body motion and setup error. No weightings were given to these structures during optimization in treatment planning. Dosimetric parameters were recorded from dose-volume histograms. Statistical analysis of parameters' association with nausea and vomiting was performed using univariate and multivariate logistic regression.
Six patients (12.2%) reported Grade 1 nausea, and 8 patients (16.3%) reported Grade 2 nausea. Also, 4 patients (8.2%) complained of Grade 1 vomiting, and 4 patients (8.2%) experienced Grade 2 vomiting. No patients developed protracted nausea and vomiting after completion of IMRT. For radiation-induced acute nausea, V40 (percentage volume receiving at least 40Gy) to the VB-T and V40>=80% to the VB-T were predictors, using univariate analysis. On multivariate analysis, V40>=80% to the VB-T was the only predictor. There were no predictors of radiation-induced acute vomiting, as the number of events was too small for analysis.
This is the first study demonstrating that a V40 to the VB-T is predictive of radiation-induced acute nausea. The vestibules should be labeled as sensitive OARs, and weightings should be considered for dose sparing during optimization in the treatment planning of IMRT.
我们旨在研究调强放疗（IMRT）治疗未分化鼻咽癌（NPC）中预测放射性急性恶心和呕吐的剂量学参数。
在这项前瞻性研究中，49 例新诊断为 NPC 的连续患者仅接受 IMRT 治疗。排除接受任何形式化疗的患者。在计划 CT 图像上勾画出背侧迷走神经复合体（DVC）以及左、右前庭（VB-L 和 VB-R，分别）。还生成了一个同时包含 VB-L 和 VB-R 的结构，命名为 VB-T。所有结构均标记为危及器官（OAR）。将这些结构加上 3mm 的三维边界，并标记为 DVC+3mm、VB-L+3mm、VB-R+3mm 和 VB-T+3mm，以考虑生理体动和摆位误差。在治疗计划的优化过程中，这些结构没有权重。从剂量-体积直方图中记录剂量学参数。使用单变量和多变量逻辑回归分析参数与恶心和呕吐的相关性。
6 例患者（12.2%）报告 1 级恶心，8 例患者（16.3%）报告 2 级恶心。另外，4 例患者（8.2%）抱怨 1 级呕吐，4 例患者（8.2%）经历 2 级呕吐。没有患者在完成 IMRT 后出现迁延性恶心和呕吐。对于放射性急性恶心，VB-T 的 V40（接受至少 40Gy 的体积百分比）和 VB-T 的 V40>=80%是单变量分析的预测因子。在多变量分析中，VB-T 的 V40>=80%是唯一的预测因子。由于事件数量太少，无法分析放射性急性呕吐的预测因子。
这是第一项表明 VB-T 的 V40 可预测放射性急性恶心的研究。前庭应标记为敏感的 OAR，并在 IMRT 治疗计划的优化过程中考虑权重以保护剂量。
