1. Department of Radiotherapy, ‘SS Annunziata’ Hospital ‘G. D’Annunzio’ University, Chieti, Italy;
2. Gemelli Advanced Radiation Therapy Center Fondazione Policlinico Universitario ‘A. Gemelli’ Catholic University of Sacred Heart, Rome, Italy;
3. Radiotherapy Unit Azienda Ospedaliera Universitaria, Verona, Italy;
4. Department of Radiation Oncology, Azienda Ospedaliera S. Gerardo, Monza, Italy;
5. Radiation Oncology Section University of Perugia and Perugia General Hospital, Perugia, Italy;
6. Radiotherapy Unit Department of Oncology, ‘Giovanni Paolo II’ Foundation Catholic University of Sacred Heart, Campobasso, Italy;
7. Radiotherapy Unit, Azienda Ospedaliera Universitaria Pisana, Pisa, Italy;
8. Department of Radiotherapy, State Hospital, Ancona, Italy;
9. Proton Therapy Unit, Department of Oncology, Azienda Provinciale per i Servizi Sanitari, APSS, Trento, Italy;
10. Department of Radiation Oncology, Ospedale Belcolle, Viterbo, Italy;
11. Department of Radiation Oncology, Centro di Riferimento Oncologico Regionale, Rionero in Vulture, Potenza, Italy;
12. Department of Radiation Oncology Centro di Riferimento Oncologico, National Cancer Institute, Aviano, Italy;
13. Radiation Oncology Center, Department of Experimental Diagnostic and Specialty Medicine - DIMES, University of Bologna, S. Orsola-Malpighi Hospital, Bologna, Italy;
14. Tecnologie Avanzate, Srl, Torino, Italy;
15. Department of Radiology, ‘SS Annunziata’ Hospital ‘G. D’Annunzio’ University, Chieti, Italy;
16. Laboratory of Biostatistics Department of Medical, Oral and Biotechnological Sciences ‘G. D'Annunzio’ University, Chieti, Italy