Department of Radiation Oncology and Division of Medical Radiation Physics, Bern University Hospital, Switzerland.
Int J Radiat Oncol Biol Phys. 2013 Nov 1;87(3):534-41. doi: 10.1016/j.ijrobp.2013.06.2053. Epub 2013 Aug 22.
Different international target volume delineation guidelines exist and different treatment techniques are available for salvage radiation therapy (RT) for recurrent prostate cancer, but less is known regarding their respective applicability in clinical practice.
A randomized phase III trial testing 64 Gy vs 70 Gy salvage RT was accompanied by an intense quality assurance program including a site-specific and study-specific questionnaire and a dummy run (DR). Target volume delineation was performed according to the European Organisation for the Research and Treatment of Cancer guidelines, and a DR-based treatment plan was established for 70 Gy. Major and minor protocol deviations were noted, interobserver agreement of delineated target contours was assessed, and dose-volume histogram (DVH) parameters of different treatment techniques were compared.
Thirty European centers participated, 43% of which were using 3-dimensional conformal RT (3D-CRT), with the remaining centers using intensity modulated RT (IMRT) or volumetric modulated arc technique (VMAT). The first submitted version of the DR contained major deviations in 21 of 30 (70%) centers, mostly caused by inappropriately defined or lack of prostate bed (PB). All but 5 centers completed the DR successfully with their second submitted version. The interobserver agreement of the PB was moderate and was improved by the DR review, as indicated by an increased κ value (0.59 vs 0.55), mean sensitivity (0.64 vs 0.58), volume of total agreement (3.9 vs 3.3 cm(3)), and decrease in the union volume (79.3 vs 84.2 cm(3)). Rectal and bladder wall DVH parameters of IMRT and VMAT vs 3D-CRT plans were not significantly different.
The interobserver agreement of PB delineation was moderate but was improved by the DR. Major deviations could be identified for the majority of centers. The DR has improved the acquaintance of the participating centers with the trial protocol.
对于复发性前列腺癌的挽救性放疗（RT），存在不同的国际靶区勾画指南和不同的治疗技术，但对于它们在临床实践中的各自适用性知之甚少。
一项测试 64Gy 与 70Gy 挽救性 RT 的随机 III 期试验，同时进行了严格的质量保证计划，包括特定部位和研究特定的问卷和模拟运行（DR）。靶区勾画按照欧洲癌症研究与治疗组织的指南进行，并且为 70Gy 建立了基于 DR 的治疗计划。记录了主要和次要方案偏差，评估了勾画靶区轮廓的观察者间一致性，并比较了不同治疗技术的剂量-体积直方图（DVH）参数。
30 个欧洲中心参与了研究，其中 43%使用了三维适形放疗（3D-CRT），其余中心使用了调强放疗（IMRT）或容积旋转调强技术（VMAT）。30 个中心中有 21 个（70%）中心的首次提交的 DR 版本存在主要偏差，主要是由于前列腺床（PB）定义不当或缺乏 PB。除了 5 个中心外，所有中心都成功地完成了第二次提交的 DR。PB 的观察者间一致性为中度，通过 DR 审查得到了改善，表现为κ值增加（0.59 对 0.55）、平均灵敏度提高（0.64 对 0.58）、总一致体积增加（3.9 对 3.3cm3）和联合体积减少（79.3 对 84.2cm3）。IMRT 和 VMAT 与 3D-CRT 计划的直肠和膀胱壁 DVH 参数没有显著差异。
PB 勾画的观察者间一致性为中度，但通过 DR 得到了改善。对于大多数中心，都可以识别出主要偏差。DR 提高了参与中心对试验方案的了解。
