ESTRO 2023 - Abstract Book

S324

Sunday 14 May 2023

ESTRO 2023

For the first 28 PP/PPP patients treated in PEARLS, radiotherapy was successfully delivered with no re-plans required. Table 1 presents IGRT verification log results.

Fewer than 1% (4/560) of fractions had a prostate/nodes deviation >10 mm, which was corrected in all cases by an intervention before treatment delivery. Of the fractions delivered, 5.9% had a deviation of >5 mm to ≤ 10 mm and 94.1% were ≤ 5 mm. The difference in the results for PPP and PP treatments was small. Only 29/560 fractions required a re-setup and, of these, 25 were due to patient positioning or anatomy (e.g. pelvic pitch, rectal gas). Conclusion The QA initiatives implemented have supported centres in delivering the treatment required for the trial. The IGRT log results provided reassurance in the quality of the IGRT guidance, independent of equipment type, and that prostate and para-aortic nodes radiotherapy can be accurately delivered. OC-0422 Treatment planning compliance rates in paediatric clinical trials: preliminary report from QUARTET S. Kelly 1,2,3 , A. Turcas 2,4,5 , C. Corning 2 , T. Boterberg 6 , L. Gandola 7 , M. Gaze 8 , G. Horan 9 , L. Padovani 10 , H. Mandeville 11,12 1 European Society for Paediatric Oncology (SIOPE), QUARTET Project, Brussels, Belgium; 2 European Organisation for Research and Treatment of Cancer (EORTC) Headquarters, Data Management, Radiotherapy Quality Assurance, Brussels, Belgium; 3 Ghent University, Faculty of Medicine and Health Sciences, Ghent, Belgium; 4 European Society of Paediatric Oncology (SIOPE), QUARTET Project, Brussels, Belgium; 5 University of Medicine and Pharmacy “Iuliu Hatieganu”, Department of Radiation Oncology, Cluj-Napoca, Romania; 6 Ghent University Hospital, Department of Radiation Oncology, Ghent, Belgium; 7 Fondazione IRCCS-Istituto Nazionale Dei Tumori, Department of Radiation Oncology, Milan, Italy; 8 University College London Hospitals NHS Foundation Trust, Department of Oncology, London, United Kingdom; 9 Cambridge University Hospitals NHS Trust, Oncology Centre, Cambridge, United Kingdom; 10 Assistance Publique Hôpitaux de Marseille, Department of Radiation Oncology, Marseille, France; 11 The Royal Marsden Hospital, Department of Radiation Oncology, Sutton, United Kingdom; 12 Institute of Cancer Research, -, Sutton, United Kingdom Purpose or Objective The QUARTET Project provides radiotherapy quality assurance (RTQA) for European paediatric clinical trials: encompassing site approvals prior to trial participation as well as treatment plan evaluation. The main goal of the project is to provide prospective individual case review (ICR) of planning data, allowing error correction prior to treatment delivery, thereby