ESTRO 2021 Abstract Book

S240

ESTRO 2021

patients developed distant metastasis and died from their disease. Progressive decrease in visual acuity after proton therapy for uveal melanoma starts within one year and results in loss of useful vision in 4 out of 5 patients, with proximity to the macula and tumor volume as the most important risk factors.

PH-0328 Current practice for selection of adult patients for proton therapy across Europe M. Tambas 1 , H.P. van der Laan 1 , R. Steenbakkers 1 , J. Doyen 2 , B. Timmermann 3 , E. Orlandi 4 , M. Hoyer 5 , K. Haustermans 6 , P. Georg 7 , N.G. Burnet 8 , K. Kirkby 9 , V. Gregoire 10 , V. Calugaru 11 , E.G. Troost 12 , F. Hoebers 13 , F.A. Calvo 14 , J. Widder 15 , F. Eberle 16 , M. van Vulpen 17 , P. Maingon 18 , T. Skóra 19 , D.C. Weber 20 , K. Bergfeldt 21 , J. Kubes 22 , J.A. Langendijk 1 1 University of Groningen, University Medical Center Groningen, Department of Radiation Oncology, Groningen, The Netherlands; 2 Centre Antoine-Lacassagne, University of Côte d’Azur, Department of Radiation Oncology, Nice, France; 3 University Hospital Essen, West German Proton Therapy Centre Essen (WPE), West German Cancer Center (WTZ), German Cancer Consortium (DKTK), Department of Particle Therapy, Essen, Germany; 4 National Center for Oncological Hadrontherapy (CNAO), Radiation Oncology Clinical Department, Pavia, Italy; 5 Aarhus University Hospital, Danish Centre for Particle Therapy, Aarhus, Denmark; 6 UZ Leuven, Department of Radiation Oncology, Leuven, Belgium; 7 MedAustron Ion Therapy Center, Department of Radiation Oncology, Wiener Neustadt, Austria; 8 The Christie NHS Foundation Trust, Christie Proton Therapy Centre, Manchester, United Kingdom; 9 University of Manchester, Division of Cancer Sciences, Manchester, United Kingdom; 10 Centre Léon Bérard, Department of Radiation Oncology, Lyon, France; 11 Institut Curie, Paris & Proton Center, Department of Radiation Oncology, Orsay, France; 12 OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden – Rossendorf, Department of Radiation Oncology, Dresden, Germany; 13 MAASTRO Clinic, GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre+, Department of Radiation Oncology, Maastricht, The Netherlands; 14 University of Navarra, Department of Radiation Oncology, Madrid, Spain; 15 Comprehensive Cancer Center Vienna, Medical University of Vienna, Department of Radiation Oncology, Vienna, Austria; 16 University Hospital Marburg, Marburg Ion- Beam Therapy Center (MIT), University Center for Tumor Diseases Frankfurt and Marburg (UCT), Department of Radiotherapy and Radiooncology, Marburg, Germany; 17 HollandPTC, Department of Radiation Oncology, Delft, The Netherlands; 18 Hôpitaux Universitaires La Pitié Salpêtrière, Department of Radiation Oncology, Paris, France; 19 Maria Skłodowska-Curie National Research Institute of Oncology, Department of Radiation Oncology, Kraków, Poland; 20 Paul Scherrer Institute, ETH Domain, Center for Proton Therapy, Villigen PSI West, Switzerland; 21 Skandion Clinic, Department of Radiation Oncology, Uppsala, Sweden; 22 Proton Therapy Center Czech, Department of Radiation Oncology, Prague, Czech Republic Purpose or Objective Among individual proton therapy (PT) centres and European countries, there are major differences regarding patient selection for PT. This is especially true for adult patients who would normally be treated with photon therapy but may benefit from the delivery of PT instead. To obtain insight in the current practice in Europe, we performed a survey on the different selection methods currently applied in the European PT centres. Materials and Methods We first designed electronic questionnaires for eight different tumour sites. The questionnaires consisted of multiple choice, checkbox and open questions regarding the application of PT for adult patients. We focused on four main topics including indications and patient selection methods and criteria, reimbursement, clinical and preclinical on-going or planned studies, and the average number of patients treated with PT per year. Results Links to the online questionnaires were sent to 23 European PT centers of which 19 (83%) participated. Major variability existed regarding the number of tumor types treated with PT (average: 4; range: 1-8) among the participating centres (Figure 1). All centers treated central nervous system tumours (CNS), while tumours of the head and neck cancer (HNC) were treated in 79% , lymphoma in 47%, gastrointestinal in 47%, breast in 32%, prostate in 26%, lung in 26% and gynecological cancers in 11 % of the centers.

For the tumour types treated with PT, an indication protocol was used by most centers (institutional: 45%, national: 30%, both: 13%, none: 12%). The most frequently reported reason for not treating certain tumour types with PT was lack of evidence for the therapeutic gain of protons over photons (30%), followed by