ESTRO 2025 - Abstract Book

S3607

Physics - Quality assurance and auditing

ESTRO 2025

Results: Seven PT and seven XT sites have completed the pre-trial QA. Twenty facility questionnaires were returned from ten PT sites and ten XT sites. Robust evaluation towards setup uncertainties and respiratory motion is for most participating XT sites not a part of the daily clinical routine. This is, however, mandatory in the PROTECT trial and must be implemented when patient inclusion begins. Beam output audits were submitted and were approved from 18 sites (nine PT, nine XT). ICR was performed for 19 patients from three different PT/XT sites. For the delineation of targets and OARs, six major and eight minor variations were reported and for five patients there were no remarks. One major and four minor variations were reported for the treatment plans. Three site visits were performed where adaptive strategies were discussed in particular. Larger margins with respect to the diaphragm motion and specific measures for the evaluation of target deviations were implemented after these visits. One annual workshop was completed with 43 participants. Conclusion: A strict pre-trial and continuous on-trial RTQA programme is feasible when conducting a large, multi-institutional phase-III clinical trial. Few major variations were reported from the individual case reviews. The mandatory requirements of the RTQA programme will likely change the way patients with locally advanced oesophageal cancer are treated with radiotherapy in Europe.

Keywords: Esophageal cancer, radiotherapy quality assurance