QUALITY ASSURANCE OF THE EORTC RADIOTHERAPY TRIAL-22931 FOR HEAD AND NECK CARCINOMAS - THE DUMMY RUN

Purpose: A dummy run was organized to test the compliance of participa ting centres with the guidelines of EORTC protocol 22931, which compar es high dose radiotherapy with concomitant radiochemotherapy in a post operative setting for patients presenting with locally advanced head a nd neck carcinomas. Methods: In a first step the participants (seven c entres, six replies) were asked to define the planning target volume ( PTV) in a given patient on the basis of clinical, surgical and radiolo gical (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 ask ed to plan a treatment following the recommendations made in the frame of the trial. Results: The first step of this dummy run emphasized wi de intercentre variations in PTV extensions. This fact raises the ques tion of the reproducibility when pooling patients in multicentric tria ls. The second step indicated a large variability in the field arrange ments which was left to the discretion of the investigators. Only thre e our of 10 of the institutions followed the ICRU 50 recommendations f or dose reporting. Moreover, protocol requirements were not met for do se distribution homogeneity in any centre. Conclusions: In order to re duce intercentre treatment heterogeneities, several actions have been taken by the EORTC Radiotherapy Group, e.g. amendments have been broug ht to protocol 22931 regarding a better definition of clinical and pla nning target volumes. Furthermore, a stricter application of the ICRU 50 recommendations for dose reporting has been sought. (C) 1998 Elsevi er Science Ireland Ltd.