Valley J F, Bernier J, Tercier P A, Fogliata-Cozzi A, Rosset A, Garavaglia G, Mirimanoff R O
Institute of Applied Radiophysics, University Center, Lausanne, Switzerland.
Radiother Oncol. 1998 Apr;47(1):37-44. doi: 10.1016/s0167-8140(97)00218-1.
A dummy run was organized to test the compliance of participating centres with the guidelines of EORTC protocol 22931, which compares high dose radiotherapy with concomitant radiochemotherapy in a postoperative setting for patients presenting with locally advanced head and neck carcinomas.
In a first step the participants (seven centres, six replies) were asked to define the planning target volume (PTV) in a given patient on the basis of clinical, surgical and radiological (CT-images) data-sets and according to the protocol guidelines. In a second phase a series of CT-reconstructed slices with on- and off-axis PTV outlines were sent to 11 centres (10 replies), which were asked to plan a treatment following the recommendations made in the frame of the trial.
The first step of this dummy run emphasized wide intercentre variations in PTV extensions. This fact raises the question of the reproducibility when pooling patients in multicentric trials. The second step indicated a large variability in the field arrangements which was left to the discretion of the investigators. Only three out of 10 of the institutions followed the ICRU 50 recommendations for dose reporting. Moreover, protocol requirements were not met for dose distribution homogeneity in any centre.
In order to reduce intercentre treatment heterogeneities, several actions have been taken by the EORTC Radiotherapy Group, e.g. amendments have been brought to protocol 22931 regarding a better definition of clinical and planning target volumes. Furthermore, a stricter application of the ICRU 50 recommendations for dose reporting has been sought.
组织了一次预试验，以测试参与中心是否符合欧洲癌症研究与治疗组织（EORTC）22931方案的指南，该方案比较了局部晚期头颈癌患者术后高剂量放疗与同步放化疗的效果。
第一步，要求参与者（七个中心，六个回复）根据临床、手术和放射学（CT图像）数据集，并按照方案指南，在给定患者中定义计划靶体积（PTV）。在第二阶段，将一系列带有轴上和轴外PTV轮廓的CT重建切片发送给11个中心（10个回复），要求它们按照试验框架中的建议制定治疗计划。
这次预试验的第一步强调了各中心在PTV范围上存在很大差异。这一事实引发了在多中心试验中合并患者时再现性的问题。第二步表明，野布置存在很大差异，这由研究者自行决定。10个机构中只有3个遵循国际辐射单位与测量委员会（ICRU）50号报告中关于剂量报告的建议。此外，任何中心的剂量分布均匀性均未达到方案要求。
为了减少各中心治疗的异质性，EORTC放疗组采取了多项措施，例如对22931方案进行了修订，以更好地定义临床靶体积和计划靶体积。此外，还寻求更严格地应用ICRU 50号报告中关于剂量报告的建议。
