Gruhl J D, Zheng D, Longo J L, Enke C, Wahl A O
Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, NE.
Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI.
Brachytherapy. 2017 Mar-Apr;16(2):373-377. doi: 10.1016/j.brachy.2016.11.008. Epub 2016 Dec 28.
The aim of this study was to compare the organ-at-risk doses to the rectum and the bladder in postoperative endometrial cancer patients who receive high-dose-rate vaginal brachytherapy (HDR-VB), when using three different methods of treatment planning: (Workflow A) individualized treatment planning before every fraction, (Workflow B) individualized treatment planning for first fraction only), and (Workflow C) using a template plan based on applicator choice and prescription specifics without patient-specific imaging or planning (standardized template approach).
Alternative plans were retrospectively created using workflows B and C for 22 patients who previously received postoperative HDR-VB using a vaginal cylinder and planned using Workflow A for endometrial cancer. The rectum and bladder were contoured on the CTs used for each fraction for dose comparison between the three methods. D, D, D, D, and V of the bladder and the rectum were compared using the two-sided Wilcoxon signed-rank test.
A total of 123 fractions were available for comparison. For Workflow A vs. Workflow B, there was no significant difference for any rectal or bladder dosimetric parameter. For Workflow A vs. Workflow C, Workflow A delivered a significantly higher median dose to the rectum than Workflow C for D, D, D, and V. Workflow C delivered a significantly higher dose to the bladder than Workflow A: D, D, D, and V. However, the magnitudes of the differences were small; the dose index difference was >75 cGy for only two fractions.
Plan standardization in HDR-VB may result in considerable time and cost savings with minimal organ-at-risk dose differences.
本研究的目的是比较接受高剂量率阴道近距离放射治疗（HDR-VB）的子宫内膜癌术后患者，在使用三种不同治疗计划方法时，直肠和膀胱的危及器官剂量：（工作流程A）每次分割前进行个体化治疗计划，（工作流程B）仅对第一分割进行个体化治疗计划，以及（工作流程C）使用基于施源器选择和处方细节的模板计划，无需患者特异性成像或计划（标准化模板方法）。
对22例先前使用阴道柱状施源器接受术后HDR-VB并采用工作流程A进行子宫内膜癌计划的患者，回顾性地使用工作流程B和C创建替代计划。在用于各分割的CT上勾勒出直肠和膀胱，以比较三种方法之间的剂量。使用双侧Wilcoxon符号秩检验比较膀胱和直肠的D、D、D、D和V。
共有123个分割可用于比较。对于工作流程A与工作流程B，任何直肠或膀胱剂量学参数均无显著差异。对于工作流程A与工作流程C，在D、D、D和V方面，工作流程A给予直肠的中位剂量显著高于工作流程C。工作流程C给予膀胱的剂量显著高于工作流程A：D、D、D和V。然而，差异幅度较小；仅两个分割的剂量指数差异>75 cGy。
HDR-VB中的计划标准化可能会节省大量时间和成本，同时危及器官剂量差异最小。
